A UK-trained Navy officer who joined Daesh turns supergrass after arrest by Kuwaiti authorities. Supergrass is a British slang term for an informer, which originated in London.

He has become one of the most senior figures to hand over intelligence on the terrorist group.

Kuwait-born Ali Omar Mohammad Alosaimi, 27, was picked up on the Iraq-Syria border on July 4, according to officials.

Alosaimi, who had three years of merchant navy officers’ training at South Tyneside College’s Marine School – one of the UK’s most prestigious maritime colleges – left his home in South Shields for Syria in April 2014.