When it's politically expedient for them not to be deemed so, of course.
The Attorney General could be given a veto over arrest warrants for foreign leaders in an attempt to placate Israeli ministers who fear war crimes prosecutions if they visit Britain.
Baroness Scotland of Asthal, who is in Jerusalem, discussed an amendment to British law that would give her office the power to review arrest warrants in private prosecutions against political figures, according to Foreign Ministry sources.
Yes, more unintended consequences attached, as is customary, to ill considered Labour legislation. Forget the UN, forget international convention or courts, a war criminal is only a war criminal if Labour say so.
Still, such a veto would come in pretty handy when potentially having to decide how to deal with former Labour Prime Ministers too, would it not?