The elected leader has said that the elected deputy leader (not part of any coup), "is talking nonsense – and he knows it."

There is no coming back from that.

Watson hit back on Saturday night, claiming the evidence was "incontrovertible". He said: "The overwhelming majority of new members joined the Labour party because they want to build a fairer and more equal society. But there is clear and incontrovertible evidence that a small group of Trotskyite activists have taken leading roles in the Labour party or are seeking to do so.

"They are also explicitly targeting Young Labour and Labour student clubs with the aim of recruiting new members. That is beyond dispute. We can't deal with this problem until we acknowledge it exists."