(1)It is an offence against the law of England and Wales for a person to engage in conduct ancillary to an act to which this section applies.
(2)This section applies to an act that if committed in England or Wales would constitute—
(a)an offence under section 51 (genocide, crime against humanity or war crime), or
(b)an offence under this section,
but which, being committed (or intended to be committed) outside England and Wales, does not constitute such an offence.
(3)The reference in subsection (1) to conduct ancillary to such an act is to conduct that would constitute an ancillary offence in relation to that act if the act were committed in England or Wales.
(4)This section applies where the conduct in question consists of or includes an act committed—
(a)in England or Wales, or
(b)outside the United Kingdom by a United Kingdom national, a United Kingdom resident or a person subject to UK service jurisdiction.