UNITE general secretary Len McCluskey called on "malcontent" Blairite MPs to "put a sock in it" today, telling back-stabbers to "get out of our union."

Speaking at Unite’s policy conference in Brighton, Mr McCluskey also vowed to spend the union's £35 million strike fund, amassed under his leadership, to tackle “bad bosses” and make them realise their “game is up.”

The union leader pulled no punches as he criticised Labour rightwingers who still seek to undermine Labour leader Jeremy Corbyn, warning them that the only people they were serving were the Tories.

Mr McCluskey said: “I say to the small but noisy group of back-bench Labour malcontents: Get behind our leader and put a sock in it."

He also pointed out that unions had been given full consultation in the development of Labour’s election manifesto, For The Many, Not The Few, and told politicians to “listen to the unions and you won’t go wrong.”

Mr McCluskey also took a swing at those who attempted to overturn his leadership in the 2016-17 Unite leadership campaign.

He urged the “lies specialists and shady machine politicians” who “sought to hijack Unite” to “get out of our union and stay out.

“We don’t need you and our solidarity will always be stronger than your smears.”

In reference to Gerard Coyne, Mr McCluskey’s challenger who is currently mired in a legal battle against Unite, Mr McCluskey said that Mr Coyne’s team, comprised of rightwingers and members of Blairite think tank Progress, “took aim at Unite, but they were really going for Jeremy Corbyn.”

Mr McCluskey defended his own leadership, which prioritises industrial struggle and the development of members, saying: “We must never let Unite become a union where members are customers rather than custodians.”

He also called on Labour to put “decent jobs and skilled work at the heart of everything” as he lamented the decline of party support in former manufacturing areas in the Midlands, Yorkshire and south Wales.

He said: “Our strength and our unity has helped our movement turn the corner.

“We need to redouble our strength and unity.

“If we do, we can open the door to a better Britain for all working people.”

Mr McCluskey paid a touching tribute to Unite members Amal Ahmadeen, Nadia Choucair and Dennis Murphy who were killed in the Grenfell Tower fire.

After paying tribute to Unite’s colleagues in the Fire Brigades Union, Mr McCluskey said that Grenfell was a “story of inequality, of corners being cut on public housing in one of the richest boroughs in Europe.

“It is a story of the folly of deregulation and competition for something as vital as safety standards and building inspections.

“It is a story about austerity and the serious cuts to fire service provisions in London.”

Mr McCluskey saluted Mexico's left-wing President-elect Andres Manuel Lopez Obrador, urging the labour movement to continue fighting for victories so that “we can hold in our hearts the knowledge that we helped create a just world for the children of tomorrow.”