If on a defendant's trial before a judge and jury for an offence—
the court must either direct the jury to acquit the defendant of the offence or, if it considers that there ought to be a retrial, discharge the jury.
Where—
the defendant may not be found guilty of that other offence if the court is satisfied as mentioned in subsection (1)(b) in respect of it.
If—
the court must either direct the jury to acquit the defendant of the offence or, if it considers that there ought to be a rehearing, discharge the jury.
This section does not prejudice any other power a court may have to direct a jury to acquit a person of an offence or to discharge a jury.
For the purposes of this section a person's evidence is contaminated where—
the evidence is false or misleading in any respect, or is different from what it would otherwise have been.