Schools have to teach religious education (RE) but parents can withdraw their children for all or part of the lessons. Pupils can choose to withdraw themselves once they’re 18.
Local councils are responsible for deciding the RE syllabus, but faith schools and academies can set their own.
It must be taught to at least GCSE level, and conflict (and religious attitudes to it) are part of the GCSE syllabus. The AQA examination board have cited Coventry Cathedral as an exemplar of religious responses to conflict.
See SACRE for more about the Coventry syllabus.