It has been called the “oldest hatred”. The way anti-Semitism has shown its face inside the Labour Party demonstrates the extraordinary way this pernicious moral disease survives by mutating, passing from host to host. It entered Labour disguised as sympathy for the Palestinian people in their struggle for nationhood, and was absorbed into an anti-capitalist and anti-American agenda that already existed on the radical Left. Its various contradictory strands gathered themselves into one giant conspiracy theory, which was then viciously turned against any member of the Labour Party, high or low, who identified as Jewish.

It hardly mattered whether they were practising and observant or not. Anti-Semitism is not interested in the content of the Jewish faith. It is a form of racism, but more than that: it is political. It presupposes that Jews instinctively work together for an undeclared common cause: in this case, the promotion of Zionism, assumed to be the underlying philosophy of the Israeli state.