History has shown how dangerous it is to assume that the hard Left are virtuous allies for social democrats

I first came across the phrase “no enemies on the left” when studying European history at university, rather longer ago than I care to admit. My understanding is that it was coined by Alexander Kerensky, who led the Menshevik revolution, though I was more aware of it in the context of the Popular Front in 1930s France.

It has been almost an article of faith for those of us who are left of centre. But in reality is it is palpable nonsense.

In my case, the penny dropped with Neil Kinnock’s speech at the 1985 Labour conference in Bournemouth, when he laid into the Trotskyite Militant Tendency. I think I should come clean here and admit that I was, and remain, an admirer of Kinnock as the man who knocked sense into the Labour party and paved the way for Tony Blair to enter Downing Street....