Millions of British households will receive a leaflet this week warning that the price of their shopping will go up if the UK leaves the European Union, as the in campaign starts to heat up before the referendum.

The Britain Stronger in Europe campaign is sending a mailout to more than 10m UK households amid signs that the referendum could be held as soon as June or July.

The leaflet, featuring a picture of a shopping trolley, says: “Being in the EU makes it cheaper to import vital goods from the EU, which means lower prices for every family. If we left the EU, the cost of these imports would increase by £11bn – meaning you and your family would have to pay more as prices go up.”

The pamphlet quotes Karren Brady, the businesswoman and member of the team on BBC1’s The Apprentice, saying EU membership is vital for trade. Sir Hugh Orde, the former police chief, argues that the EU is good for security.

Polls suggesting the race has narrowed. A survey by Survation in the Mail on Sunday found support building for an exit from the EU, with 42% in favour of leaving, 38% for remaining and 20% yet to make up their mind. Until recently, most polls found the in campaign was ahead.

Cabinet ministers are not allowed to declare for either side until David Cameron achieves his promised renegotiation with the EU, which is likely to happen in February at the earliest. But several are now beginning to line up for each camp. Nigel Lawson, the Eurosceptic former Tory chancellor, said a current cabinet minister would lead the out campaign, with the name to be revealed in due course.

Last week, Chris Grayling, the leader of the House of Commons, was the first to signal his intention to campaign for an exit. Other strongly Eurosceptic figures in Cameron’s top team include Iain Duncan Smith, the work and pensions secretary, and Theresa Villiers, the Northern Ireland secretary.

With the prospect of a deal nearing, senior Conservative figures have now been encouraged to make similar pronouncements for the in campaign. Liz Truss, the environment secretary, and Nicky Morgan, the education secretary, have made arguments for staying in the EU in the past week.

Nick Herbert, a Eurosceptic former minister who led the campaign to stay out of the euro, has effectively declared he will campaign to stay in the EU, after he was named head of the new Conservatives for a Reformed Europe group alongside Sir Eric Pickles, the former Tory chairman and ex-communities secretary.



A report in the Sunday Times suggested Cameron was confident of delivering some surprise concessions from the EU. He has struggled to get agreement from the other 27 leaders in the bloc on his plans to limit migrant benefits.

However, the report said he was approaching a deal on alternative proposals, including rebranding Britain as a different sort of member state in the outer circle of Europe, and reviving the idea of an “emergency brake” on EU migration to Britain, enabling the government to block new arrivals if public services became overwhelmed.

It said Cameron would try to change domestic law to make clear that parliament is sovereign and that courts are not bound by Europe’s charter of fundamental rights. This would come on top of some of Cameron’s other demands that are believed to have been secured already, including a red card system for groups of national parliaments to block EU laws and protections for non-eurozone countries.

Nick Clegg, the Liberal Democrat former deputy prime minister, appeared on the BBC’s Andrew Marr Show on Sunday making the case for staying in the EU but saying that parts of Cameron’s renegotiation were insubstantial.