Jeremy Corbyn will mobilise Labour’s entire shadow cabinet and the leaders of 11 trade unions representing millions of workers, amid growing alarm among remain campaigners that Britain could be on the verge of voting to leave the EU.

David Cameron has stood aside from active campaigning in order to make way for a push by Labour , as the party’s MPs admit that the response on the doorstep in its heartlands suggests leave campaigners’ warnings about immigration are making significant inroads.

Speaking at an event in central London, Corbyn will issue “an appeal to the whole labour movement and Labour supporters across Britain to support a remain vote in next week’s referendum”. The leaders of 11 trade unions are expected to join Corbyn, including Len McCluskey from Unite, Tim Roache from GMB, and Dave Prentis from Unison. There are fears that voters do not realise that the vast majority of Labour MPs support staying in the EU.

The planned intervention comes after a pair of Guardian/ICM polls suggested that support for leaving the EU is strengthening, with phone and online surveys showing a six-point lead for Brexit. Leave now enjoys a 53%-47% advantage once “don’t knows” are excluded, according to research conducted over the weekend, compared with a 52%-48% split reported by ICM a fortnight ago.

In other polling today, a YouGov poll for the Times puts leave on 49% and remain on 39%, while an ORB poll for the Telegraph found that among those certain to vote, support for the Brexit campaign is on 49%, compared with 48% for remain.

A source within the remain camp said Downing Street had shifted from being “utterly convinced” of victory in the referendum battle, to a “blind panic”. The source claimed that strategists had convened an emergency meeting on Friday, but a spokesman for Britain Stronger in Europe denied the suggestion.

The spokesman added that the campaign was sticking to the same message it had always made but was simply using the penultimate week of campaigning to “widen out the people delivering the message”.

The sense of panic among remain campaigners has emerged since Labour MPs started reporting negative feedback from voters in their constituencies. One senior figure in the party claimed that politicians all over the country, and particularly in working-class heartlands, had said that they believed their own areas would swing towards Brexit.



Another MP who is active in the remain campaign said the response from some constituents had been alarming, with some accusing politicians of being traitors for campaigning to stay in. He said the most noticeable message was about the idea that Britain could control its borders if it left the EU.

Facebook Twitter Pinterest Gordon Brown has called on Labour supporters to get behind the in campaign. Photograph: Will Oliver/EPA

Tim Farron, the Liberal Democrat leader, said the referendum has turned into a game of “political Russian roulette”. He said he wanted campaigners to wake up to the fact that “there is a huge danger that we will lose this”.

He added: “We have less than 10 days to save Britain and make sure that we stay as an outward-looking nation, standing tall in the world. I fear Britain’s place at the heart of Europe is at serious risk.”

Prof John Curtice of Strathclyde University, who analyses available referendum polling data on his website whatukthinks.org, said that with the ICM data, the running average “poll of polls” would stand at 52% for leave and 48% for remain, the first time leave has been in such a strong position.



“These results are consistent with the generality of numbers over the last couple of weeks, in which there has been some weakening in the remain position,” he said. “It was already plain that this race was far closer than the prime minister intended and he must now be feeling discomfort at the thought that the outcome really could be in doubt.”

Labour grandees who have held cabinet and shadow cabinet positions, including Charles Clarke, Ed Balls, Charlie Falconer, Harriet Harman, Alan Johnson, Jacqui Smith, Alan Milburn and Jack Straw, also released a joint statement warning that leaving the EU would hit public services and frontline workers.

They said that 525,000 public sector employees would lose their jobs in the wake of a British exit from the EU, a figure strongly disputed by Vote Leave. “Leaving Europe is a leap into the dark and is a risk for Britain’s public services that we cannot afford to take,” they added.

The TUC general secretary, Frances O’Grady, will claim that Brexit will cost the public purse £30bn a year, which is enough to fund the whole of NHS England for three months. “Where would our NHS be without the 50,000 dedicated health staff from the EU? If we leave the EU, it could unleash an NHS staffing crisis and the longest waiting lists we’ve ever known,” she will say.

But a spokesman for Vote Leave said the figures from Labour and the TUC were predicated on economic analysis based on “highly negative assumptions”, which still showed that the economy would grow after a British vote to leave.

“By taking back control we can invest £100m extra a week for our hospitals, cut VAT and restore control of both immigration and trade deals creating jobs and increasing wages,” he claimed.

Facebook Twitter Pinterest David Cameron has taken a back seat on the campaign front recently, as Labour seeks to appeal to its members. Photograph: Handout/Facebook via Getty Images

Angela Eagle, the shadow business secretary, said she felt the campaign was “on a knife edge” and agreed that Cameron’s TV appearances “do not help with the Labour vote”.

“We are trying to get our messages heard above the general psychodrama of the blue-on-blue attack,” she said. “This whole thing is about Tory big beasts having a battle like rutting stags, but it’s far more important, this vote, than any of that.”

Cameron should let new voices make case for remain, says Labour Read more

In his speech on Monday, Gordon Brown argued that a campaign that was bringing together Corbyn, John McDonnell and “my old friend Peter Mandelson” showed the breadth of Labour support for staying in the EU.

“What sort of message can we send to the world on 23 June if we, Britain, who consider ourselves one of the most internationally minded, who consider ourselves outward-looking and engaged, decide to walk away from our nearest neighbours?” he asked.

He admitted that globalisation had left people behind, including in Labour constituencies, but he refused to tackle specific questions about immigration, instead accusing media outlets including the Sun and BBC of having “an agenda”. Brown was heckled by one journalist calling on him to answer the question.

The former shadow chancellor Ed Balls warned that remain cannot afford to be seen as the party of the status quo on migration, or risk losing key swing Labour voters in the referendum. He said there needed to be direct controls on migration and new border controls that went beyond the deal sealed by Cameron in February.

Balls said: “It is not good enough to says controls on benefits reached by David Cameron is as good as it gets. Most people do not think that goes far enough, and we cannot look like supporters of the status quo. Europe still doesn’t work well enough for Britain.

“There’s still too much waste and bureaucracy from Brussels, and while a limit has been secured on the benefits paid to migrant workers I don’t think that can be the end of the story. We need to press Europe to restore proper borders, and put new controls on economic migration.”

Meanwhile, Conservative out campaigners expressed frustration with their party leader and the chancellor, George Osborne, for suggesting that Brexit could hit pensioners and disabled benefits.

Andrew Percy MP said: “This stumbling campaign seems to have been reduced to a series of threats. With no positive message to tell, they are reduced to scare tactics – doing their best to frighten the most vulnerable people in our country into voting to remain in the EU.”

His intervention comes as the Sun newspaper publishes a major front page editorial today calling on British people to vote to leave the EU. The tabloid claims: “To remain means being powerless to cut mass immigration which keeps wages low and puts catastrophic pressure on our schools, hospitals, roads and housing stock.”