Where a justice of the peace is satisfied that—
the justice shall issue a summons directed to that person requiring him to attend before the court at the time and place appointed in the summons to give evidence or to produce the document or thing.
If a justice of the peace is satisfied by evidence on oath of the matters mentioned in subsection (1) above, and also that it is probable that a summons under that subsection would not procure the attendance of the person in question, the justice may instead of issuing a summons issue a warrant to arrest that person and bring him before such a court as aforesaid at a time and place specified in the warrant; but a warrant shall not be issued under this subsection where the attendance is required for the hearing of a complaint ... .
A summons may also be issued under subsection (1) above if the justice is satisfied that the person in question is outside the British Islands but no warrant shall be issued under subsection (2) above unless the justice is satisfied by evidence on oath that the person in question is in England or Wales.
A justice may refuse to issue a summons under subsection (1) above in relation to the summary trial of an information if he is not satisfied that an application for the summons was made by a party to the case as soon as reasonably practicable after the accused pleaded not guilty.
In relation to the summary trial of an information, subsection (2) above shall have effect as if the reference to the matters mentioned in subsection (1) above included a reference to the matter mentioned in subsection (2B) above.
On the failure of any person to attend before a magistrates' court in answer to a summons under this section, if—
the court may issue a warrant to arrest him and bring him before the court at a time and place specified in the warrant.
If any person attending or brought before a magistrates' court refuses without just excuse to be sworn or give evidence, or to produce any document or thing, the court may commit him to custody until the expiration of such period not exceeding one month as may be specified in the warrant or until he sooner gives evidence or produces the document or thing or impose on him a fine not exceeding £2,500 or both.
A fine imposed under subsection (4) above shall be deemed, for the purposes of any enactment, to be a sum adjudged to be paid by a conviction.