When is expert evidence admissible

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Cross border evidence. Disclosure pilot scheme. Factual evidence. Specific disclosure. Sign-in Help. Admissibility of expert evidence Admissibility of expert evidence Practice notes. The following Dispute Resolution practice note provides comprehensive and up to date legal information covering: Admissibility of expert evidence Admissibility of expert evidence—CEA Is expert evidence admissible and 'reasonably required'—Rule Access this content for free with a trial of LexisPSL and benefit from: Instant clarification on points of law Smart search Workflow tools 36 practice areas.

Back Step 1 of 2 Basic information. Step 1 Step 2 Name. Miss Mrs. Name Click to edit. Name No Content These fields are required. The family's case was entirely based on inference. They relied on three documents: a witness statement of a Mr Salenko a Ukrainian investigator that included reference to what Mr Salenko had been told by another investigator about Ms Moore's movements on the night of Mr Pring's death; 'maps' produced by Mr Salaneko in reality photos of locations near to the crime scene, marked up by reference to mobile phone data to show the apparent location of Ms Moore in the aftermath of Mr Pring's death — based on information given to him by the same investigator; and a summary or 'protocol' of mobile phone data obtained from Ms Moore's records and covering the relevant period, prepared by a Ukrainian Internal Affairs Captain and signed by two witnesses.

In relation to the specific documents, the court found as follows: The witness statement: this contained hearsay evidence that was admissible in that it recorded what Mr Salenko was told by another investigator.

If the information that had led to the annotation of the maps did not require an expert to opine, then the evidence was admissible as hearsay fact. If it did, it was admissible as expert evidence. The 'maps': the court could not determine whether or not the annotations on the 'maps' could only derive from an analysis by a person qualified to give expert evidence. In other words, it was possible that a lay person could have drawn the same conclusions if faced with the same underlying information.

The protocol: the court could not determine whether an expert would have been required to produce the protocol. The fact that the source of the evidence could not be identified was not an objection. The protocol was accordingly admissible either as hearsay evidence of fact, or of both fact and opinion.

Comment The case clearly sets out the difference between evidence which will be subject to CPR 35's restrictions and that which will not be.

The opposing party must respond setting out which of the expert's conclusions are admitted, and in relation to those that are disputed, what the issue is. The content of an expert's report or a statement prepared by an expert must comply with CrimPR In assessing what to include in the report, in order to comply with CrimPR To the extent that an expert's evidence is also in the form of witness statement, it must also comply with Section 9 Criminal Justice Act and Rule 16 of the Criminal Procedure Rules.

The primary facts upon which the expert's opinion is based, such as a description of what is found and its location must be proved by admissible evidence. This evidence will derive from the expert's own personal knowledge or experience, or evidence of other witnesses. Section of the Criminal Justice Act allows a party to rely on hearsay evidence to assist in proving the facts upon which the expert's opinion is based, if those facts are contained in a statement made for the purposes of criminal proceedings or an investigation , by a person who had first-hand knowledge of the matters stated.

However, the fact that the expert is relying upon such evidence and the details of the maker of that preliminary evidence should be disclosed in the notice serving the expert evidence on the other party Archbold paragraph and CrimPR Further support for a robust approach to be taken in relation to expert evidence and the content of reports can be found in R v Hamilton [] EWCA Crim.

An expert can express his conclusions in terms of the degree of support that a forensic procedure provides for that conclusion and based on his experience in the field provided that:. There is no database of facial features from which to calculate the frequency with which those features appear in the population at large or sub-sets of the population.

It is crucial that experts are instructed who are capable of conveying their findings and conclusions in a way that is easily understood by the lay person. As a participant in criminal proceedings, the expert has a duty to ensure "that evidence whether disputed or not, is presented in the clearest and shortest way" Crim.

Reports should be robust, logical, transparent and balanced. If not, or if an expert's report opens up issues which require further exploration, or which clash with other expert evidence on the file, a supplementary report could be requested from the expert.

It remains open to the prosecutor to discuss with the expert by telephone, the contents of which may need to be added to the Disclosure Schedule, whether the matters requiring exploration are sufficiently straight-forward as to be best capable of development or resolution by an additional report, or whether they need to be explored by way of a case conference.

A case conference with an expert may be required pre or post a charging decision. Experts are usually more than willing to participate in the conferences as they appreciate the importance of having a full understanding of the issues before the trial commences.

Care should be taken to avoid delaying a conference until a late stage in the proceedings as it may be too late at that point to obtain additional reports, if required, or to correct any misunderstandings. An early conference can assist the preparation of the case for trial. The following steps should be taken in relation to conferences with prosecution experts and the prosecution team:.

Note: There are risks in having a case conference before an expert has committed his opinion to writing. This is because there needs to be a clear, auditable record of the expert's original view - not merely for disclosure purposes, but in order that everyone attending the conference understands clearly the views of the expert in relation to the evidence.

Conferences may be required for a number of reasons. In particular, they provide an opportunity to explore with experts whether there exists:. The case conference is also an opportunity to see how the expert "presents" when their views are explored around the conference table. If the purpose of the conference is to explore or resolve evidence issues, then the cost of that conference in terms of experts' fees is an investigative one for the police to bear.

This applies whether the conference occurs at the pre or post charge stage. If the conference is held for other purposes, expert fees may be met, at least in part by the CPS. Where the CPS may be asked to meet some of the expert's costs, this should be discussed in advance of arranging the conference with the Unit Head. Section 81 of the Police and Criminal Evidence Act Crown Court cases and Section 20 Criminal Procedure and Investigations Act magistrates court cases provide for the making of rules requiring the parties to proceedings to make advance disclosure of any expert evidence that they propose to rely on.

A party to proceedings is prohibited from adducing such evidence, without leave of the court, should advance disclosure not be made. In addition, that party must provide a copy of, or a reasonable opportunity to inspect, anything on which any such examination, measurement, test or experiment was carried out. A party may not introduce expert evidence if that party has not complied with this rule, unless every other party agrees or the court gives permission. These provisions do not apply to the service of summaries of experts' conclusions, in relation to which, please see Use of SFR and Summaries of Expert Evidence above.

Expert witnesses are participants in criminal proceedings. Therefore they must act in accordance with the overriding objective of the Criminal Procedure Rules which is to ensure that criminal cases are dealt with justly.

Dealing with a criminal case justly includes acquitting the innocent and convicting the guilty, whilst dealing with the case efficiently and expeditiously. Good case management will require the expert to address at an early stage any alternativehypothesis.

To do so, the experts should be provided with a copy of any Defence Statement as soon as possible. Examples of how experts can assist in terms of complying with CrimPR 1 and CrimPR 3 include preparing reports that are short, concise and easily understood by lay people, complying with timescales set out in letters of instruction and attending case conferences.

The aim is to limit the issues in dispute, ensuring that the bench or jury can focus on the key issues in the case and have a clear understanding of each issue. The court may direct the experts to discuss the expert issues in the proceedings; and prepare a statement for the court of the matters on which they agree and disagree, giving their reasons. Prosecutors should take the initiative in seeking to arrange a conference between experts, only seeking a court order, where necessary.

Experts should be asked to set out in a joint statement the basic science and accepted principles underlying their field of expertise and the points where they agree and disagree.

These points can be put to the Magistrates or jury by way of formal admission, leaving them to decide upon the issues in dispute. In the case of R v Henderson and others, it was held that these meetings should take place in the absence of legal representatives with a careful and detailed minute prepared for the purposes of disclosure.

It was also emphasised that the trial judge should be prepared to exclude evidence of an expert witness who fails to comply with such a direction to discuss his evidence. Where co-defendants cannot agree who should be the expert, the court may select the expert from a list prepared or identified by them, or direct that the expert be selected in another way. Under CrimPR In addition, the court may give directions about the payment of the expert's fees and expenses and any examination, measurement, test or experiment which the expert wishes to carry out.

Although these provisions relate to co-defendants, prosecutors will have sight of reports and should be alive, particularly in multi-handed cases, to the dangers of confusing the jury with large amounts of expert evidence, often covering the same points. In these circumstances it is part of the prosecutor's duty to assist the court in actively managing the case to raise the need for a single joint report. It is likely that once a Defence expert is instructed, that expert may wish to have access to the material analysed by the prosecution expert in the completion of his report.

In criminal proceedings, the court has a duty to retain and preserve the exhibits in a case, which it entrusts to the Prosecution Team, usually the police. For guidance on how to respond to requests for Defence access to such material, please refer to guidance on Exhibits.

It is essential that requests for access to exhibits are dealt with in an expeditious manner as failure to respond to these requests could result in delay and criticism from the court.

It also needs to be noted that in a commercial market for the provision of forensic science and other expert evidence, many prosecution providers will wish to charge for the provision of documentation to the Defence expert and for allowing the expert access to their premises, equipment and staff.

The following points are designed to assist prosecutors in addressing these requests. They should be read in conjunction with the guidance on Exhibits :. Investigators are under a duty to consider all of the material gathered in the course of an investigation and decide whether it is relevant to that investigation, and, in relation to material that is not being used as evidence, the prosecutor must decide if it should be disclosed.

Unused material should be disclosed to the Defence if it assists the defence case, or undermines the prosecution case. This might include any draft report prepared by an expert instructed by the prosecution. Material that has a bearing on the competence or credibility of an expert witness or is generated by him in the course of his analysis is relevant to a criminal investigation and potentially should be disclosed in subsequent proceedings.

Examples of material that might be disclosed include:. The expert is a third party to those proceedings and is not bound by the provisions of the Criminal Procedure and Investigations Act The police and CPS seek to impose these obligations on the expert as part of their contractual relationship with the expert. This is why it is vital to provide the expert with a copy of the CPS Guidance for Experts on disclosure, unused material and case management.

Experts will facilitate proper disclosure in criminal proceedings if they remember that they should follow this process in relation to material generated by them in the case:. An expert witness must make all of his material available to other experts and cannot refuse to disclose material such as accreditation documentation, staff training records or details of software developed to analyse information on the basis of the need to protect his intellectual property rights.

For more detail on the duties of disclosure relevant to expert witness, see Chapter 36 of the Disclosure Manual. Guidance on dealing with cases where the competence or credibility of an expert witness is in doubt can be found at Chapter 37 of the Disclosure Manual. The following Guidance is additional to and is not intended to replace Chapter The guidance is informed by CPS experience in dealing with such cases and also takes account of the changed forensic science landscape following closure of the Forensic Science Service FSS.

Forensic science providers FSP may include private companies, government agencies, public organisations, academic research departments and law enforcement agencies. The issues may involve the methodology and systems used by the expert and might be capable of impacting on cases involving other experts employed by the same FSP or another organisation. Disclosure to the defence in current investigations will be governed by CPIA principles.

In past cases the test to be applied for disclosure is whether the information received might affect the safety of the conviction this is the common law test set out in paragraph 72 of the Attorney General's Guidelines on Disclosure.

The overriding principle in deciding whether, and to what extent, action is needed in current and past cases will be the need to maintain public confidence in the criminal justice system. Whilst it is impossible to provide an exhaustive list of sources, examples include the following:.

The remainder of this section will deal with these decisions sequentially:. Frequently, the CPS will require further information before the decisions above can be made. Prosecutors will assess on a case-by-case basis whether it appropriate to seek the further information directly or to request the investigator to obtain the further information. The disclosure test is applied on an individual case basis and the following factors will be relevant:. Whilst the factors referred to above will be relevant to prosecutors in applying this test, the overriding consideration is whether the conviction remains safe taking into account the totality of the evidence considered by the court that convicted the defendant.

Where the disclosure test is satisfied CPIA test in current cases; common law test in past cases , the prosecutor will determine what material will be sent to the defence.

Further guidance on what to include can be found in Chapter 37 of the Disclosure Manual. Prosecutors must ensure that sensitive material is not included in the disclosure package sent to the defence.

Particular care should be taken to check any sensitivity which might be attached to details of complaints to regulatory bodies. Where appropriate, CPS should contact the regulatory body to check whether the material is in the public domain and to discuss redaction, or obtaining a summary of, the material, should any sensitive material require disclosure.

The disclosure letter to the defence should be sent with a covering letter. In current cases and highly exceptionally in past cases , the CPS will determine whether to instruct a second expert to re-do the work or review the work of the discredited expert. It may be possible for the work to be re-done where the relevant exhibits remain available and intact otherwise, the second expert will conduct a full review of the work by reference to all available case materials. Where the relevant expert is a pathologist, a further post mortem may be appropriate where the body of the deceased remains available.

Prosecutors should consult with the police and HM Coroner. In deciding whether to instruct a second expert, prosecutors will take into account the following factors:. In addition to consulting with the police, it may be appropriate for prosecutors to consult with the expert's regulatory body in selecting a second expert. The regulatory body may already have instructed other expert s to review the work of the discredited expert in relation to complaint s made to that regulatory body.

Prosecutors should act expeditiously in instructing a second expert, particularly in cases involving a custody time limit.

In current cases, prosecutors must determine on a case-by-case whether to continue to rely on the expert. The decision will usually be made following consultation with the police and, where appropriate, with the expert's regulatory body. The CPS will take into account the factors above. Consideration should be given as to whether the expert should be used in any future cases. An example would be a one-off error by the expert which is unlikely to be repeated and which is not indicative of inadequate working practice generally on the part of the expert or of systemic failure on the part of the FSP or other organisation at which the expert works.

A decision not to consider disclosure in current and past cases beyond the case in question must be made by a lawyer at level E or above. It will usually be appropriate to seek written assurances from the FSP or other organisation or from the relevant regulatory body that they are satisfied that the error will not be repeated.

In consultation with the police, the CPS Area will assess the number and geographical span of current cases in which disclosure is to be considered. Police systems can be used to trawl for cases.

In rare cases, prosecutors will consider whether to include other cases handled by the same FSP or other organisation at which the expert has worked. This consideration will typically arise where the methodology, systems or safeguards used by the FSP or other organisation at which the expert works are called into question.

The Directorate will consider whether to take a coordinating role in disclosure across the service. Consideration should also be given to whether the expert has worked for other prosecuting authorities and if so those authorities should also be informed. Disclosure decisions in current cases will always be made on a case-by-case basis.

Where the CPIA disclosure test is met, disclosure will be made to the defence in accordance with the principles summarised above. In order to decide if a review of past cases is required, prosecutors should refer to Legal Guidance on Finalised cases at Reviewing finalised cases. Every effort should be made to minimise the number of appearances the expert is required to make in court and to ensure their evidence is deployed to the greatest effect.

This can be done through ensuring that cases are properly managed in accordance with the principles set out above, and effective case management at court.

For example, it is advisable to ask the court at the Pre-Trial Preparation Hearing to fix a date and time for the prosecution expert to attend, ensuring that the defence expert attends at the same time. If the case involves a number of very technical issues which the jury needs to understand it may be useful for the expert to provide his or her evidence in two stages.

Diagrammatic and photographic illustration, so long as it has been seen and approved by the expert witnesses, particularly the use of body-map technology can be of considerable assistance to the witness as well as to the judge and jury.

Advocates can deal with such evidence in a similar fashion when opening the case. Prosecutors should consider requesting experts to prepare such a document in conjunction with the Defence expert to assist the jury in its deliberations. Examination in chief should be prepared with particular care so as to ensure that the jury are given the clearest possible presentation of the evidence and its relevance to the issues in the case.

Particular care is needed to present the findings at a pace which enables the jury to follow the evidence. Topics should be taken sequentially, and in a clear and logical manner so as to ensure the jury understands the conclusions and the reasoning behind the conclusions.

Cross examination of experts requires particular care and preparation. Where necessary, the points of challenge to a defence expert should be discussed with the prosecution expert in conference, who may also provide a view on the credentials of the defence expert. In considering how the Defence evidence is to be challenged, it is essential that the issues in dispute are identified. This may be done following joint conferences between the prosecution and defence see above.

Once the issues in the case are identified, the advocate should decide the key points to be challenged.

The expert should deal with all of these points in chief. When considering how to cross examine the Defence expert, the following considerations may assist:. The prosecution expert should be present, if possible, when the Defence expert is called to give evidence. It should not be assumed that the only way in which to challenge a Defence expert is by the prosecution calling its own expert.

Other bases of challenge include:. The courts have indicated that they are prepared to refuse leave to the Defence to call expert evidence where they have failed to comply with CrimPR; for example by serving reports late in the proceedings, which raise new issues Writtle v DPP [] EWHC See also: R v Ensor [] 1 Cr. Prosecutors should be prepared to explore with a prosecution expert, if necessary whether the Defence expert is in sufficiently expert in the field and whether he has the right qualifications and experience to give the opinion sought from him.

An expert completely lacking in the requisite knowledge or experience should be subject to an application to exclude his evidence; or to an application that the judge orders him to confine his evidence to matters that are within in his experience.

Challenges to the admissibility of expert evidence on the grounds that the expert lacks the requisite qualification or experience should be raised with the Defence and the judge at the earliest opportunity;. Some experts will seek to reach conclusions based upon an incomplete reading of the evidence choosing to disregard accepted facts which do not assist their conclusions, or who demonstrate in their reports that they have not understood those facts.

They may also take into account irrelevant matters or matters not adduced in evidence upon which they form an opinion;. Conclusions in reports with degrees of support for those conclusions should not be overstated. One such example is a laser expert in respect of speeding offences who only uses the test results that go in his favour and "omits" those that do not, thereby misleading the court by omission;.

Whilst there is no requirement for an organisation or individual to be accredited to any national or international standard before results they generate are admissible as evidence, the absence of accreditation for example, in accordance with ISO standards for forensic service providers who undertake laboratory activities can result in evidence being excluded if it renders the evidence unreliable, or it can affect the weight to be attached to it.

Similarly, there is no requirement for a technique to have been accepted by the wider scientific community prior to being admitted into evidence, but again, this may affect the degree to which it can be relied upon or the weight to be attached to it; and.

Often a case may turn on a well-argued difference of opinion between Prosecution and Defence experts. R v Kai Whitewind [] 2 Cr. This does not detract from the prosecutor's duty of continued review under the Code. Accordingly, at paragraph 38 of Gian, it was held in relation to expert evidence from the prosecution:. That was the jury's function The jury was confronted with a choice between the rival arguments.

It was their task to choose between them. The fact that it was faced with a choice does not afford any basis upon which the judge should have withdrawn that choice from them. The CPS is only responsible for the costs of an expert witness in connection with work done on case presentation.

All investigative costs, at whatever stage of the proceedings, must be met by the investigator, usually the police, regardless of the stage in the proceedings at which the expert is instructed, which agency identifies the need for expert evidence or who it is that instructs the expert. Investigative costs are accrued when expert evidence is required in accordance with the investigator's duty under the Criminal Procedure and Investigations Act to pursue all reasonable lines of enquiry.

Where the expert evidence is relevant to prove whether the defendant is guilty of the offence with which he is charged, it is an investigative cost. In the context of psychiatric evidence, this means that the police will meet the cost of expert evidence on the defendant's ability to form the requisite mens rea and will also meet the cost of expert reports on diminished responsibility because this evidence is relevant to the issue of whether the defendant is guilty of the offence of murder.

Conversely, the CPS will meet the cost of psychiatric reports which deal with fitness to plead. This evidence is not an investigative cost because it is not relevant to whether the defendant is guilty of the offence. In many cases an expert will, as part of his or her professional duty, address more than one issue. The starting point is to consider the purpose of the instruction. For example, if no issue has been raised about fitness to plead and a report is required to address diminished responsibility the purpose of instructing the expert is to test the evidence to prove the offence.

The likelihood that the psychiatrist will address fitness to plead or to be tried as a routine part of the report, does not change the purpose of the instruction.

On occasion the same expert will be asked to report twice: once for one purpose and once for another. The separate preparation costs should be dealt with according to the purpose test. If an expert is instructed to prepare a report dealing with evidential issues as well as fitness the CPS will be responsible because fitness will be determined before the evidential issues.

Regardless of the payment arrangements for preparation the CPS will always be responsible for the cost of attendance.

Where the CPS position is that the police are responsible the basis must be made clear. The CPS should set this out explicitly, for example:. This is therefore an investigative cost to be borne by the police. It is likely that a psychiatrist will address fitness to plead or to be tried as a routine part of the report, but this does not change the purpose of the instruction. Experts' fees can be substantial. It is essential that expert witness fees in relation to presentation costs are agreed in advance of the trial as it is difficult to negotiate fees after the event.

Where fees have been made clear to the expert, claims resulting from unauthorised work may be refused. For details of the fees paid to different types of witness, please see Witness Expenses and Allowances. In those rare cases where the CPS instructs an expert, please note the following steps to be taken:. This applies whether an expert has already been instructed by the police or is being instructed for the first time by the CPS. Approval must be obtained from an individual with the appropriate level of financial delegation for expert fees exceeding those detailed in the scales of guidance.

This is a matter for agreement with the expert according to the nature and complexity of the task and the work involved. Consideration should be given to the material that needs to be supplied to the expert.

A page count of relevant statements and documentary exhibits may assist in reaching an agreement as to the number of hours required. For court attendance, a day and half day fee should be agreed.

The scales assume a normal court day The expert should only be paid for time travelling if the distance is in excess of 25 miles. The maximum hourly rate for travelling should be half the hourly fee agreed with the expert for court attendance.

Travel and subsistence rates must also be made clear and a copy of the rates must be forwarded to the expert witness. The mileage rate payable for travel by private car is 25p per mile.

Exceptionally, if the expert can show that they had to use their car because there was no public transport available, there was a considerable saving of time and money or because they are disabled or infirm, a higher rate of 45p per mile is payable. Rail travel will be at standard class and expert witnesses are not entitled to day subsistence. The expert should be asked to produce a detailed breakdown of the work undertaken date, time, description etc.

A copy of the completed expert fee form should be retained. If necessary a revised invoice should be obtained. Where the invoice is correct it must be authorised by a person with the appropriate level of financial delegation and forwarded to the National Finance Business Centre, Wakefield, for payment.

If the assignment is cancelled for example, the expert is not required to give evidence at court and he has been given prior notice of this whether verbally or in writing of one week, no cancellation fee will be paid. However, work already properly undertaken up to the point of notification of the cancellation will be paid in the above terms. If the assignment is cancelled with less than one week notice, a cancellation fee will be paid, subject to satisfactory proof of loss of earnings.

Note that notwithstanding the above, no cancellation fee will be paid if other work is undertaken on the date cancelled, regardless of the amount of notice given.

Letter of Instruction Template. The Royal Society has published a Royal Society DNA primer for the courts as a working tool for the judiciary, designed to assist the judiciary when dealing with forensic evidence in the courtroom. DNA Deoxyribonucleic acid is found in the mitochondria and nucleus of each cell. In the nucleus which is what is analysed by the expert in the vast majority of criminal cases the DNA is arranged into 23 pairs of chromosomes; half inherited from the mother and half from the father.

Except in the case of identical twins, different combinations of DNA are inherited and therefore each person's DNA is unique. However, it is important to remember that current techniques used in forensic science do not allow for each difference to be examined with a view to establishing a unique whole genome profile for use in the criminal justice system.

A profile is obtained through analysis of particular and specific areas or loci of a DNA strand, which are known to be widely different.

A standard process known as DNA is used which involves analysis of 16 loci in a DNA strand, each producing between one and two results, which is given a numerical value known as an allele.