When Jeremy Corbyn was first accused of laying a wreath beside the grave of a terrorist involved in the Munich massacre, his response was unequivocal.

“Absolutely not,” he retorted in May last year, when asked if he had honoured Atef Bseiso, a prominent Palestinian allegedly assassinated by Israeli operatives in Paris in 1992. “I was at a Palestinian conference...we were searching for peace in the Middle East.”

Mr Corbyn was responding to the extraordinary claim that 12 months before being appointed leader of the Labour Party, he had joined a delegation of Palestinian officials at a ceremony which included tributes to members of Black September.

The organisation is among the world’s most infamous terror groups, responsible for the assassination of a Jordanian prime minister and most notably, the murder of 11 Israeli athletes and coaches at the 1972 Olympic Games in Munich.

Bseiso, head of intelligence for the Palestine Liberation Organisation (PLO), was regarded as one of the planners of the Munich massacre, during which eight heavily armed terrorists infiltrated the Olympic village and took hostages in a bid to secure the release of 234 Palestinians jailed in Israel. Two were killed in the initial struggle and the remainder died in a bungled rescue attempt.