UNITE general secretary Len McCluskey told critics of Jeremy Corbyn today to be less “feral” and “hysterical” in a stark challenge to the Labour right.

Mr McCluskey told ITV’s Peston on Sunday that there was “nothing wrong” with criticism of Mr Corbyn’s leadership of the Labour Party.

But he urged critics to be “a little bit more constructive” about supporting the Labour leader.

Mr McCluskey singled out a core “small rump” of right-wing Labour MPs bent on undermining Mr Corbyn. “Day in, day out, the first thing they thought about was ‘how do we criticise and attack’,” he said.

The union leader, who is a noted leftwinger and stalwart supporter of Mr Corbyn, said that he would prefer to see more support from Blairite MPs.

“There’s nothing wrong with criticising the leadership if you have a particular view, but it should be less feral, less hysterical and more constructive.

“That way, we will have a better chance of having a united party in order to gain power.”

In the build-up to the May local elections, Mr McCluskey blasted “Corbyn-hater” MPs in a New Statesman article, singling out Chris Leslie, Neil Coyle, John Woodcock, Wes Streeting and Ian Austin for particular criticism.

Though he stated that he did not wish to see prominent critics of Mr Corbyn kicked out of the party, Mr McCluskey said, on the question of deselecting Labour MPs, that parliamentary representatives must answer to their members.

Following on from his public comments last week that MPs should not act as if they have a “job for life,” Mr McCluskey told Robert Peston that there have always been methods of holding representatives to account.

“Accountability has always been there within the Labour Party. There have always been trigger ballots for MPs,” he said.

Mr McCluskey defended Labour’s policy on Europe, arguing against arch-Blairite Peter Mandelson that the party’s best strategy for economic growth is to begin “a negotiation with Brussels” that will allow “frictionless access to the single market,” while remaining outside it.

The union leader said that “we can get tariff-free access to the single market and a customs union, as opposed to the customs union,” through serious negotiation and assured viewers that Jeremy Corbyn’s Labour Party could handle negotiations with Europe far better than Prime Minister Theresa May’s administration.

Asked whether former London mayor Ken Livingstone, who is suspended from the Labour Party due to his claim that Hitler supported zionism in the 1930s, should be kicked out, Mr McCluskey said: “If there was a rule in the party against stupidity, then he and lots of other people should have been excluded.”

He added: “I reject the idea that my party — a party that I have been in for 47 years — is a toxic Labour Party that is anti-semitic and misogynistic. That’s just nonsense.”