Related Rule
United Kingdom of Great Britain and Northern Ireland
Practice Relating to Rule 88. Non-Discrimination
Section E. Apartheid
The UK LOAC Manual (2004) states:
Additional Protocol I extends the definition of grave breaches to include the following:
c. the following, when committed wilfully and in violation of the Conventions or the protocol:
(3) practices of apartheid and other inhuman and degrading practices involving outrages upon personal dignity, based on racial discrimination. 
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 16.25.
The UK Geneva Conventions Act (1957), as amended in 1995, punishes “any person, whatever his nationality, who, whether in or outside the United Kingdom, commits, or aids, abets or procures the commission by any other person of, a grave breach of … [the 1977 Additional Protocol I]”. 
United Kingdom, Geneva Conventions Act, 1957, as amended in 1995, Section 1(1).
Under the UK ICC Act (2001), it is a punishable offence to commit a crime against humanity as defined in Articles 7(1)(j) of the 1998 ICC Statute. 
United Kingdom, ICC Act, 2001, Sections 50(1) and 51(1) (England and Wales) and Section 58(1) (Northern Ireland).