2. Competence and compellability

The starting rule is that a competent witness can be compelled to testify. A witness who refuses, after an order of the court, is in contempt. The exceptions, people who may be competent but are not compellable, are heads of state, diplomats under the Vienna Convention, members of international organisations (including UNAMSIL), infants, persons of defective intellect, judges in their own cases, a spouse in many of the situations set out below, and a banker asked to prove the bank's books when the bank is not a party. The last of those is section 6 of the Bankers' Books Evidence Act 1879. If the privilege or the immunity is waived, the witness is an ordinary witness.

A witness gives evidence on oath or on affirmation. A false statement is perjury. The language of the court is English. An interpreter is used where the witness does not understand it.

Children were, for a long time, governed by R v Brasier. A child who did not understand the nature of an oath could not be sworn. Statute later allowed an unsworn statement from a child of tender years who understood the duty to tell the truth, under section 38(1) of the Children and Young Persons Act, R v Hayes replaced the religious form of the test with a secular one. The child must understand that taking the oath, or speaking in the proceedings, is a solemn matter, and that he has a special duty to tell the truth. There is no fixed age of "tender years". The working ages are these. R v Wallwork treated the evidence of a girl of five as undesirable. R v Wright and Ormerod is the case. The child was five. The point in the report is that a complaint cannot be used as consistency unless the child has herself given that account. A child under eight should not testify. That is a working rule. It is not the holding of Wright and Ormerod. The case that called a child of five undesirable is R v Wallwork. The working ages are still about eight to ten, and a child is often sworn between ten and twelve if the Hayes test is met.

Defective intellect used to turn on the oath. In R v Hill a man confined in a lunatic asylum was held competent because he understood the oath and the duty to tell the truth. The modern test is Hayes. In R v Bellamy a witness with a mental age of about ten did not satisfy it. A witness who is deaf and cannot speak may still give evidence, as R v Ruston recognised, through a person who can interpret the signs. A witness who is drunk should not be sworn while he is unfit: R v Paines is the adjournment. If a witness becomes incoherent after being sworn, the judge should stop, have the witness stand down, and tell the jury to ignore what was said. It names Whitehead for that, without a year or any facts,. In R v Stretton the Court of Appeal would not interfere with a judge who declined to recall an epileptic witness.

The accused is not a competent witness for the prosecution. He is competent for the defence. In a Sierra Leone trial he has three choices. He may give sworn evidence, and be cross-examined. He may make an unsworn statement from the dock, which is not tested by cross-examination. Or he may rely on a statement he made to the police. The choice is his.

A spouse is, in general, not competent for the prosecution. The exceptions, where the spouse is competent and can be compelled for the prosecution, are a crime of violence against the spouse, a sexual offence against a child of the family, an offence that injures the spouse's liberty or health, treason, and the cases covered by the Evidence Act 1877. For the accused, the spouse is competent but not, in general, compellable. The exceptions, where the spouse can be compelled to give evidence for the accused, are violence, injury to health or liberty, and treason. For a co-accused, the spouse is competent only with the husband's or wife's consent, again excepting those same cases. That is the rule.