4.-

(1) This section applies where on the trial of a person the question arises (at the instance of the defence or otherwise) whether the accused is under a disability, that is to say, under any disability such that apart from this Act it would constitute a bar to his being tried.

(2) If, having regard to the nature of the supposed disability, the court are of opinion that it is expedient to do so and in the interests of the accused, they may postpone consideration of the question of fitness to be tried until any time up to the opening of the case for the defence.

(3) If, before the question of fitness to be tried falls to be determined, the jury return a verdict of acquittal on the count or each of the counts on which the accused is being tried, that question shall not be determined. . .

(4) Subject to subsections (2) and (3) above, the question of fitness to be tried shall be determined as soon as it arises.

(5) The question of fitness to be tried shall be determined by a jury . . .

(6) A jury shall not make a determination under subsection (5) above except on the written or oral evidence of two or more registered medical practitioners at least one of whom is duly approved . . .

4A.--

(1) This section applies where in accordance with section 4(5) above it is determined by a jury that the accused is under a disability.

(2) The trial shall not proceed or further proceed but it shall be determined by a jury-

(a) on the evidence (if any) already given in the trial;

and

(b) on such evidence as may be adduced or further adduced by the prosecution, or adduced by a person appointed by the court under this section to put the case for the defence,

whether they are satisfied, as respects the count or each of the counts on which the accused was to be or was being tried, that he did the act or made the omission charged against him as the offence.

(3) If as respects that count or any of those counts the jury are satisfied as mentioned in subsection (2) above, they shall make a finding that the accused did the act or made the omission charged against him.

(4) If as respects that count or any of those counts the jury are not so satisfied, they shall return a verdict of acquittal as if on the count in question the trial had proceeded to a conclusion.

(5) A determination under subsection (2) above shall be made -

(a) where the question of disability was determined on the arraignment of the accused, by a jury other than that which determined that question;

and

(b) where that question was determined at any later time, by the jury by whom the accused was being tried."