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Competence and Compellability

Updated: 24 July 2018|Legal Guidance


Any person is a competent witness and is capable of giving evidence but this is subject to two exceptions which are set out in the guidance below.

All competent witnesses may be compelled by the Court to testify. However, there is an exception relating to the Defendant and his or her spouse or civil partner. These witnesses are only compellable to give evidence against their partner in limited circumstances as set out below.

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 they are unable to understand questions put to them as a witness and give answers to them which can be understood [Section 53(3) of the YJCEA 1999].
  • 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) of the YJCEA 1999). A co-accused can only give evidence for the prosecution once he or she ceases to be a co-accused (for example, following a guilty plea).

Determining competence

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 under Section 53(4) of the YJCEA 1999 will be easy to establish.

The exception under Section 53(3) of the YJCEA 1999 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 coherent 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 appointed under Section 29 of the YJCEA 1999.

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 [2010] EWCA Crim 4, on the subject of competency, the Court of Appeal stated that:

“... 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.”

This approach was confirmed by the Court of Appeal in the case of F [2013] 1 WLR 2143. There, the Court held that the judge’s ruling was wrong in law as the exercise carried out by the judge was not a fair test of the witness' competency. The judge had substituted the issue of the interpreter's difficulties in communicating for the test of whether the witness could understand questions and give intelligible answers.

In the case of R v. Watts [2010] EWCA Crim 1824, it was held by the Court of Appeal that the competency test is satisfied if the witness is able to understand the question put to him (or her) and give answers to them which can be understood. Furthermore, those who are competent to give evidence should be assisted to do so, for example, with the assistance of intermediaries.

The Court of Appeal in the case of R v. Sed [2004] 1 WLR 3218, held that the test of competence set out in Section 53 did not require a witness to understand all the questions put to her and for all her answers to be understood. It was a matter for the judge to determine competence, taking into account the effect of the witness's performance as a whole and whether there was a common and comprehensible thread in her responses to the questions.

Section 54 YJCEA 1999 sets out the procedure to be followed when determining the competency of a witness. In summary:

  • 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 Court must treat the witness as having the benefit of any special measures directions which the Court has given or proposes to give in relation to the witness; 
  • 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 must be decided before the witness is sworn or starts to give evidence and ideally prior to the start of the trial. In the case of a prosecution witness, it was held in the case of Yacoob (1981) 72 Cr App R 313 that the question should be raised and decided at the beginning of the trial.

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 examination-in-chief has been given in a pre-recorded video interview admitted under Section 27 YJCEA 1999, where the child witness might subsequently be unable to provide intelligible answers in cross examination.

However, the incremental implementation of pre-recorded cross examination (Section 28 of the YJCEA 1999) should enable early identification of cases with issues of competency.

In other instances, if the Court rules the witness incompetent at cross-examination stage, the judge should direct the jury to ignore the witness’ evidence (see case of Whitehead (1866) LR 1 CCR 33).

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 [2010] 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 the Legal Guidance chapter entitled ‘Guidance on prosecuting crimes against older people and in Victims and Witnesses who have mental health issues and/or learning disabilities’.

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 or Civil Partners, below.

Witness Summons

Prosecutors are reminded that where they are not satisfied that the witness will attend court voluntarily; they can apply for a witness summons. A witness summons can either require a person to give evidence or require a person to produce documents needed as evidence.

The procedure is set out in Sections 2 to 3 of the Criminal Procedure (Attendance of Witnesses) Act 1965. A person, who disobeys a witness order or summons requiring him or her to attend Court, is guilty of contempt of the court if he or she fails to attend without just cause. He or she may be punished summarily by that Court as if his or her contempt had been committed in the face of the Court. The maximum penalty is three months’ imprisonment.

The Court in Popat (2009) 172 JP 24 emphasised that it is the disobedience of a summons which represents the contempt and there is no requirement for an arrest warrant to have been issued in addition.

The relevant rules on application for witness summons are set out in Part 17 of the Criminal Procedure Rules. See in particular Rule 17.8 which sets out the Court’s power to vary requirements so the Court may shorten or extend a time limit under this Part.

Please see below for the position regarding the compellability of spouses or civil partners in criminal proceedings.

File review

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 reliable (paragraph 4.6).

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 the decision to prosecute.

A Prosecutor concluding at the review stage that a witness is not competent by virtue of Section 53(3) of the YJCEA 1999 should ensure they have considered the matter thoroughly. Such a significant and rare decision should be discussed with, and authorised by, a District Crown Prosecutor or above. The potential ramifications for the witness in both the present and future proceedings should not be underestimated.


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. (See the case of Powell [2006] 1 Cr App R 468 and R v B [2010] EWCA Crim 4).

Sworn and unsworn evidence

The competence of a child, in particular whether the child should give sworn or unsworn evidence is covered by Sections 55 and 56 of the YJCEA 1999.

Section 55 of the YJCEA 1999 provides that the witness cannot be sworn for the purposes of giving evidence on oath unless the witness has attained the age of 14 and has a sufficient appreciation of the solemnity of the occasion and of the particular responsibility to tell the truth which is involved in taking an oath.

Therefore, children under the age of 14 should give unsworn evidence and this shall be received in evidence by the Court: see Section 56 of the YJCEA 1999.

With regards to children above the age of 14, the party seeking to have the witness sworn should satisfy the Court, on a balance of probabilities, that the child has attained the age of 14 and has a sufficient appreciation of the matters in question.

Prosecutors should refer to ‘Safeguarding Children: Guidance on Children as Victims and Witnesses’ when considering whether to call a child to give evidence.

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 an assault on, or injury or a threat of injury to the spouse or civil partner; 
  • An allegation of an assault on, or injury or a threat of injury to 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 of 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 (witness summons pursuant to Section 169 of the Serious Organised Crime and Police Act 2005) is one that should be exercised with sensitivity and discretion. Prosecutors are reminded that applying for a witness summons should be regarded as a last resort as the consequences for not attending court are serious. The witness summonsed may be arrested by the police and taken to the Court if the witness does not attend Court. Before any application for a witness summons is made, the Prosecutor must ensure that they have up to date information from the officer in the case.

When making the decision to compel a witness to attend Court to give evidence against a spouse or civil partner, Prosecutors should bear in mind that the witness may be distressed and this could lead to them becoming a ‘hostile witness’ or even refusing to give evidence altogether, which could potentially place them in contempt of Court.

Prosecutors should bear in mind that the refusal of a witness to attend Court may be brought about through fear. If this is considered to be a possibility, Prosecutors should ask for further information from the police and consider the use of Section 116 of the Criminal Justice Act 2003 (CJA 2003). The CJA 2003 gives 'fear' a wide definition and it will include fear of the death or injury of another person or of financial loss. Further guidance on this can be found in the Hearsay Guidance.

Please note that 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 [2003] Q.B. 1222, CA (Civ. Div.)).

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 abuse cases can be found in ‘Care and Treatment of Victims and Witnesses’ and in ‘Domestic Abuse Guidelines for Prosecutors’.

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 the Unit Head.

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