One frontbencher said: ‘I don’t think it’s appropriate. He hardly had the British interests at heart.’

Former Home Office Minister Ann Widdecombe said: ‘It seems to me a bit of an odd choice, but diplomacy has no bounds.’

The senator was an influential figure in the Northern Ireland peace process, capable of swinging Irish-American opinion as head of the Kennedy family – descended from an emigré from County Wexford.

Ted Kennedy was pilloried by Loyalists after he compared the British presence in Ulster to America’s involvement in Vietnam in 1971.