Grand Master - , 1:22 pm On 10 Oct 2017
WHAT IS COMPETENCE
Competence refers to the legal ability to give evidence in court. Before a witness can give evidence in court he must first be a competent witness.
WHO IS A COMPETENT WITNESS
Section 175 of the Evidence Act 2011 provides thus:
'All persons shall be competent to testify, unless the court considers that they are prevented from understanding the questions put to them or from giving rational answers to those questions by reason of tender years, extreme old age, disease whether of body or mind or any other cause of the same kind'
By the provision of this section all persons are presumed competent to testify. As the court stated in Asuquo Eyo Okon v The State, 'since all persons are competent to testify, until the competence of a witness to testify is challenged for any of the reasons stated in the section, there is in my view no obligation on the court to determine the competence of a witness to testify'.
The effect of this is that the court would not suo motu carry out an examination on all witnesses before it to determine their competence before receiving their evidence, except it appears to it that the witness before it may not be a competent one as is the case with child witnesses.
The test introduced by section 175 the Evidence Act 2011, which is similar to Section 53(3) of the Youth Justice and Criminal Evidence Act 1999 of the UK, is that of intellectual capacity and not of age.
Thus, witnesses of any age are competent witnesses so far as they possess sufficient intelligence to understand the question put to them and of providing rational answers to those questions.
Under section 175 of the Evidence Act 2011, the competence of a witness can be challenged on the ground that the witness is incapable of understanding the questions put to him or of giving rational answers to those question, because he is;
a) A child
b) An aged Person
c) Suffering from disease whether of body or mind.
d) A person of unsound mind.
As stated by the court in Asuquo Eyo Okon v The State, the competence of witnesses under the Evidence Act 2011 can only be challenged on these grounds and no more.
Where the competence of any person to be called as a witness is challenged on any of the ground stated in the section, the proper course of action is for the court is to carry out a preliminary investigation to ascertain the competence of such person. It may do this by putting forth questions to the person in open court which may have nothing to do with the matter before the court. If as a result of this investigation the court comes to the conclusion that the person is unable to understand questions or to answer them rationally, then he cannot be a witness; but if he passes the test then he may be a witness.
Where the competence of a witness is in question, the effect of a failure to carry out a preliminary investigation to ascertain the competence of the potential witness before taking his testimony was considered in Mbele v The State, the Supreme Court had to determine the competence of a child witness of 10years old. It stated inter alia that this preliminary investigation is a condition precedent and a failure to carry it out is fatal to the case and would invalidate a conviction where this irregularity occasioned a miscarriage of justice.
This examination must be carried out in open court. In R v Dunn, where the judge carried out the investigation of a child witness to determine his competence out of court, it was held that this was illegal and sufficient to invalidate a conviction.
WHAT IS COMPELLABILITY?
Compellability on the other hand deals with whether a witness can be mandated to give evidence; this can be through the use of a summon if the venue is a magistrate court or subpoena if the venue is a High Court.
WHO IS A COMPELLABLE WITNESS?
Once ascertained that a person is a competent witness, the issue of compellability comes second.
Although all compellable witnesses are competent witnesses as the court would not compel a person to do that which is not competent to do; however not all competent witnesses are compellable.
A witness is compellable if he can be mandated to give evidence by law. The court may compel a witness by serving him with a summon or subpoena as the case may be, depending on whether the venue is a Magistrate Court or a High Court, where he fail to obey, he may render himself liable to contempt proceeding.
Certain persons are not compellable under the Evidence Act and other relevant laws. Such persons include, the president, vice president, governors, deputy governors, diplomats, legal practitioners, bankers amongst others.
The following witnesses are not compellable witnesses
1. The President, Vice President, Governors, Deputy Governors.
2. Diplomats, members of their families, members of the official or domestic staff, members of the families of their official staff.
4. Justices, Judges, Grand Kandi, or President of a Customary Court of Appeal.
5. Public Officers.
6. Legal Practitioners.
It should be noted that although a witness may be a compellable witness he cannot be compelled to answer all questions put to him. For instance, section 183 of the Evidence Act 2011, provide that; 'no one is bound to answer a question if the answer to it would, in the opinion of the court, have a tendency to expose the witness or the wife or husband of the witness to any criminal charge, or any penalty or forfeiture which the judge regards as reasonably likely to be preferred or sued for'
Thus, if the question put to a witness is in the opinion of the court have a tendency to expose the witness or the wife or husband of the witness to any criminal charge, he cannot be compelled to answer them. This may be referred to as the right against self-incrimination.
 (1988) ANLR 173 at 186.
 (1990) 4 NWLR (Pt. 145) 484.
 (2014) 3 SCR 490
 Section 308 of The Constitution of the Federal Republic of Nigeria, 1999.
 Section 1 of the Diplomatic Immunities and Privileges Act.
 Section 177 of the Evidence Act 2011
 Section 188 of the Evidence Act 2011
 Section 191 of the Evidence Act, 2011.
 Section 192 of the Evidence Act 2011.