Jeremy Corbyn has hailed a 100,000-strong surge in Labour members since the EU referendum as evidence of a “political sea change” and insisted he is in tune with the new public mood, as he seeks to quash a rebellion by many of the party’s MPs.

As the government prepares to push ahead with a vote on the renewal of the Trident nuclear deterrent on 18 July in a bid to highlight the deep divisions in Labour over defence policy, Corbyn made it clear he would stand firm against his many critics in Westminster.

The prominent backbencher and Labour MP for Aberavon, Stephen Kinnock, said the referendum result meant Labour needed “a persuader, not a protester”, to hold the Conservative government to account, through the tough negotiations with the rest of the EU that will lie ahead.

But in a defiant article for the Guardian, Corbyn said Britain needs “leadership and a clear strategy,” in the wake of the EU referendum result; and sought to claim the findings of the Chilcot report as a victory for his own style of politics.

“The damning verdict of the Chilcot report on the Iraq war confirmed that while the political establishment got it disastrously wrong, the majority of our people called it right,” he said. “This political sea change is also what led to my own election nine months ago, by 60% of Labour members and supporters.”



Corbyn added that while he was willing to “reach out” to sceptical MPs and participate in talks with union leaders to “bridge the gap and work together more effectively”, he had no intention of stepping down. “Those who want to challenge my leadership are free to do so in a democratic contest, in which I will be a candidate,” he said.

The jump in Labour members takes the new total 503,143 – the highest number in modern history. Corbyn said: “Our priority must now be to mobilise this astonishing new force in politics, and ensure people in Britain have a real political alternative”.

The Keep Corbyn campaign, coordinated by the grassroots group Momentum, believes the bulk of new members would back Corbyn in a challenge; but a rival Saving Labour campaign has been signing up members of the public who want him to stand down.

News of the surge in Labour members emerged as Whitehall sources suggested MPs would be asked on 18 July to confirm that construction of all four submarines needed to maintain a continuous at-sea nuclear deterrent should go ahead.

The renewal of Trident is a highly contentious issue among Labour MPs and supporters. Photograph: Handout/Getty Images

Defence, and in particular the future of Trident, is one of the key policy areas which divides Corbyn from many of his MPs. He is expected to offer MPs a free vote, arguing that the ongoing review of foreign policy by his shadow defence secretary, Emily Thornberry, means the party has no fixed position.

But Trident backers – including John Woodcock, whose Barrow constituency is home to the shipyard where the new submarines will be built – insist the party’s official policy remains to back renewal. “We voted on it at conference last year,” he said.

It emerged on Thursday that rebel MPs were holding off challenging Corbyn for the party’s leadership to allow those talks to continue over the weekend.

Owen Smith, the former shadow work and pensions secretary who had been known to be gathering Labour MPs’ signatures to support a leadership run, released a statement on Thursday saying he would not launch a challenge while the talks were going on.

“I believe that all of us whose priority is to restore unity in the Labour movement and give us a chance to defeat our only true enemy, the Tories, should give these talks every chance to succeed. That is what I intend to do and I urge all my colleagues to do likewise,” he said.



That makes it hard for Angela Eagle, the former shadow business secretary who had previously announced that she was preparing to challenge Corbyn, to take any action before the weekend.

However, Eagle’s backers have insisted she has more signatures than the 20% of the parliamentary party needed to launch a challenge, and is in a “holding pattern”.

Watson is said to be keen to have more time to try to persuade Corbyn that his position has become untenable, after scores of resignations from the shadow frontbench. But Corbyn’s article suggested he had no intention of standing aside.

Tom Watson, Labour’s deputy leader, who is currently involved in talks with Corbyn about how to prevent the party descending into civil war, is a strong supporter of Trident. Other trades unions that are key backers of Corbyn, including the GMB, are also in favour of Trident renewal.