Jeremy Corbyn has said that Sir Keir Starmer’s insistence that the pair were never friends is “primary school stuff”.

The former Labour leader, who has been blocked from running as the party’s candidate in Islington North at the next general election, said that he had always seen Sir Keir as a “colleague” when the pair worked together.

The veteran left-winger, who sits in the Commons as an independent, also hit out at Labour’s recent controversial social media campaign attacking the Prime Minister.

It comes after Sir Keir denied he was ever a friend of his former leader.

“It makes me sad, actually. I don’t know why he says that.

“I mean, I worked with Starmer. He was in the shadow cabinet. I went to Brussels with him. Yeah, I worked with him, I worked with lots of people,” Mr Corbyn told LBC.

Asked if he regarded Sir Keir as a friend, he said: “I regarded him as a colleague. I never regarded him as a friend. I didn’t spend time hanging out with him.

“A friend is somebody you go out for a meal with, have a chat, call their house.

“So, why he suddenly announced to the world that I was a friend and then a short time later, now I was not a friend. This is primary school stuff.”

He also labelled the attack ads as “bad news all around”.

“I think the idea that you say something unbelievably awful about an opponent as a kind of gesture towards them is not very good or very sensible.

“I do not believe in that sort of thing.”

The National Executive Committee last month backed a proposal from Sir Keir not to endorse Mr Corbyn in contesting his north London seat for Labour at the next election.

Mr Corbyn has criticised the move at the time as a “shameful attack on party democracy”