Definition of competency
A witness is competent if he or she can lawfully be called to give evidence.
The principle is set out in section 53(1) of the Youth Justice and Criminal Evidence Act 1999 (YJCEA 1999):
'At every stage in criminal proceedings all persons are (whatever their age) competent to give evidence'.
There are two exceptions:
- A person is not competent to give evidence in criminal proceedings if it appears to the court that he is not a person who is able to understand questions put to him as a witness and give answers to them which can be understood [section 53(3)].
- A person charged in criminal proceedings is not competent to give evidence in the proceedings for the prosecution (whether he is the only person, or is one of two or more persons, charged in the proceedings) [section 53 (4)].
Definition of compellability
A witness is compellable if he or she may lawfully be required to give evidence. Most witnesses who are competent can be compelled to give evidence. The only exception relates to spouses and civil partners who are only compellable to give evidence against their partner in limited circumstances - see Spouses and Civil Partners, below.
When reviewing a file of evidence, it is important to identify any witnesses whose competence may be called into question at trial, and to consider this when deciding whether there is a realistic prospect of conviction. The Code for Crown Prosecutors instructs prosecutors to consider whether evidence can be used and whether it is relible (paragraph 4.7).
It is also important to decide if a witness is compellable and, if not, whether she or he will give evidence voluntarily. This may affect your decision to prosecute.
A prosecutor concluding at the review stage that a witness is not competent by virtue of section 53(3) should not do so lightly. Such a significant - and rare - decision should be discussed with, and authorised by, a DCP or above. The potential ramifications for the witness in both the present and future proceedings should not be underestimated.
At a trial, the judge or the magistrates will decide if a witness is competent. An incompetent witness is one who comes within one of the exceptions set out above.
The exception in section 53(4) will be easy to establish.
The exception within section 53(3) is entirely witness specific and there should be no presumptions or preconceptions. Provided the witness can understand the questions put to him or her (by both parties) and can also provide understandable answers then he or she is competent. This assessment of competency should, where applicable, take into account techniques or measures that can be used to assist the witness to give his or her evidence, for example the use of a Registered Intermediary.
The Registered Intermediary must not be asked to comment on credibility or competence; their role is to assist the witness to give evidence to the best of his or her ability.
In R v B  EWCA Crim 4, on the subject of competency, it was said:
'... the competency test is not failed because the forensic techniques of the advocate (in particular in relation to cross-examination) or the processes of the court (for example, in relation to the patient expenditure of time) have to be adapted to enable the witness to give the best evidence of which he or she is capable.'
Section 54 YJCEA 1999 sets out the procedure to be followed when determining the competency of a witness. In precis:
- the competence of a witness can be raised by a party to the proceedings or by the court of its own motion;
- the party calling the witness must satisfy the court on the balance of probabilities that the witness is competent;
- the determination of competence must be in the absence of the jury;
- expert evidence may be given;
- any questioning of the witness will be conducted by the court in the presence of the parties.
Questions of competency should ideally be decided at the start of the case but in any event before the witness is sworn or starts to give evidence. However, issues of competency may only become apparent after the witness has begun to give evidence or during cross-examination. This may be particularly so for child witnesses whose evidence in chief has been given in a pre-recorded video interview admitted under section 27 YJCEA 1999.
Credibility and reliability
Competency should not be confused with credibility or reliability. At the stage when the question of competency is being decided upon judges or magistrates are not deciding whether a witness is, or will be, telling the truth or giving accurate evidence. Questions about credibility and reliability go to the weight of the evidence, not to the competence of the witness.
'...The purpose of the trial process is to identify the evidence which is reliable and that which is not, whether it comes from an adult or a child. If competent, as defined by the statutory criteria, in the context of credibility in the forensic process, the child witness starts off on the basis of equality with every other witness'. R v B  EWCA Crim 4.
Prosecutors should also recognise that the competence of a witness is a separate issue to that of the mental capacity of a witness. Further information can be found in Guidance on prosecuting crimes against older people and in Victims and Witnesses who have mental health issues and/or learning disabilities - prosecution guidance.
Children of any age can be called to give evidence; their competence depends upon their understanding not their age. As far as competency is concerned the same test is applied to child witnesses as for adult witnesses.
There is no additional, non-statutory, test to be applied for children based upon previous attitudes towards the ability of children to give evidence. The principles are encompassed in and governed by statute. Each assessment of competency is witness specific; there is no minimum age below which a witness will be deemed incompetent.
If you are considering calling a child to give evidence you should refer to Safeguarding Children: Guidance on Children as Victims and Witnesses.
Spouses or Civil Partners
Section 80 of the Police and Criminal Evidence Act 1984 (PACE) is the statutory provision which governs the competence and compellability of spouses and civil partners in criminal proceedings.
Spouses or civil partners of a person charged in proceedings are generally competent to give evidence for the prosecution. The only exception is if the spouse or civil partner is jointly charged. If they are, neither is competent or compellable to give evidence, on behalf of the prosecution, against the other unless the spouse or civil partner witness has already pleaded guilty, or the proceedings in respect of the spouse or civil partner witness have been discontinued.
Spouses or civil partners are competent and compellable to give evidence on behalf of the defendant or the defendant's co-accused.
The prosecution can only compel a spouse or civil partner to give evidence for the prosecution in cases which involve:
- an allegation of violence against the spouse or civil partner;
- an allegation of violence against a person who was at the material time under the age of sixteen years;
- an alleged sexual offence against a victim who was at the material time under the age of sixteen years; or
- attempting, conspiring or aiding and abetting, counselling and procuring to commit the offences in the categories above.
If a spouse witness is divorced from the defendant or the civil partnership comes to an end before he or she gives evidence, the former spouse/civil partner is competent and compellable to give evidence as if that person and the accused had never been married or had never been civil partners.
Section 80 PACE does not apply to a defendant's partner to whom he or she is neither married nor in a civil partnership.
The decision to compel a witness to attend court with a view to giving evidence for the prosecution against his or her expressed wish is one that should be exercised with sensitivity and discretion.
When making the decision to compel a witness to attend court to give evidence against a spouse or civil partner you should bear in mind that the witness may be distressed. You will not know how the witness will react. He or she:
- may become a "hostile witness";
- may give good evidence; or
- may refuse to give evidence and be in contempt of court.
You should bear in mind that the refusal of a witness to attend court may be brought about through fear. If you consider that this may be a possibility, you should ask for further information from the police and consider the use of section 116 Criminal Justice Act 2003.
The provision of support from Victim Support, the police and other agencies may be very important to witnesses in these circumstances.
Further guidance on reluctant witnesses in domestic violence cases can be found in Care and Treatment of Victims and Witnesses and in Guidance on Prosecuting case of Domestic Violence
Marriage of defendant and witness
The marriage of a defendant to a witness before the trial makes the witness non-compellable for the prosecution, unless the charge is one of those set out above.
In the case of a defendant in custody, a prison governor may give an unconvicted inmate permission to marry.
However, there is no power to prevent the marriage between a prisoner on remand and a witness for the prosecution, even if this might make the spouse a non-compellable witness for the prosecution in the pending trial (R (CPS) v Registrar-General of Births, Deaths and Marriages  Q.B. 1222, CA (Civ. Div.)).
Level of authority
The decision to compel a spouse or civil partner to attend court to give evidence against his or her spouse or civil partner should only be taken by a senior lawyer, experienced in dealing with sensitive cases.
This is a sample of our (approximately) 4 page long Witnesses Competence And Compellability notes, which we sell as part of the Criminal Evidence Notes collection, a O package written at City Law School in 2017 that contains (approximately) 176 pages of notes across 31 different documents.
Witnesses Competence And Compellability Revision
The following is a plain text extract of the PDF sample above, taken from our Criminal Evidence Notes. This text version has had its formatting removed so pay attention to its contents alone rather than its presentation. The version you download will have its original formatting intact and so will be much prettier to look at.
WITNESSES: COMPETENCE AND COMPELLABILITY Rules:
To be allowed to give evidence, a witness must be "competent"
To be required to give evidence (eg. by a witness summons), a witness must be "compellable" Competence
Governed by Youth Justice and Criminal Evidence Act 1999 Presumption: All Witnesses are competent to give evidence (s53(1)) General Test - applied by Court when the Witness' competence is questioned (s53(3))
A person is not competent to give evidence in criminal proceedings if it appears to the court that he is not a person who is able to: (a) understand the questions put to him as a W, and (b) give answers to them that can be understood
Questioning W's Competence s55(1) - Open to party/court of its own motion to question any Witness' competence s53(3) - That party must then satisfy the criteria (prove) on the balance of probabilities Understanding Questions Put & Giving Understandable Answers
When deciding, the court should consider Witness as having benefit of any available special measures
Witness does not need to be aware of status as a W - only to understand questions and give understandable answers.
◦ Infant who can only speak in baby-language: not competent
◦ Young child who can speak and understand basic English: competent
R v Sed - Do not require 100% comprehension/comprehensibility
◦ For Judge to determine question of competence, taking into account Witness' performance as a whole
◦ Consider whether there is a common comprehensible thread in answers
◦ If on critical matters the Witness can be intelligible - it is for the Jury to determine his reliability and cogency.
R v B - Additional guidelines on child Witnesses:
◦ Competence is Witness-specific - there should be no presumptions or preconceptions
◦ Witness does not need to be intelligible on every question
◦ It is a matter of judgement - age is a factor but decision concerns the individual Witness
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