Chris Williamson, Labour MP for Derby North, has spent the past few years as if on some kind of warped mission to prove himself as the leading troll of British Jews in the country.

As the JLC pointed out in its letter to him this week, he has repeatedly smeared our loyalty and questioned our motivations in calling out antisemitism within the Labour Party. But, this week, he crossed a line.

On Monday, he signed the Holocaust Educational Trust’s book of remembrance, posting a self-congratulatory picture of himself doing so on Twitter. That a man such as Mr Williamson should sign the book is a desecration of Holocaust Memorial Day. If Mr Williamson was in any way sincere in signing it, he would have renounced his past behaviour and allied with those who call out antisemitism within his party.

But of course he has done no such thing because, in signing the book, he was repeating the pattern, making a mockery of the Holocaust — behaviour which was rightly labelled “repulsive” by Karen Pollock, the chief executive of the HET.

Nothing better illustrates the points made by Rachel Riley in her address to the HET the next day.

Mr Williamson behaves with impunity because he is effectively licensed to do so by his party leadership. They are the real villains of the piece, mouthing platitudes about tackling antisemitism while doing next to nothing about it.

Ms Riley has emerged as an eloquent and powerful voice against bigotry not because she has chosen such a path but because the behaviour of Chris Williamson and the Corbynites has forced the role on her. We have said before, and will carry on saying, that this is an issue that matters not just to the Jewish community but to anyone who opposes bigotry.

That does not include the Labour leadership.