Eurosceptic MPs challenge Cameron over border claims

won’t be in Europe anymore. So that will really be a foreign country for us.”

Mr Cameron later said that Britain could be denied information about “terrorists or criminals travelling around Europe” if it opted to leave the European Union.

He said: “There are any number of opposition politicians in France who would love to tear up the excellent agreement we have with France to make sure that we have our borders on their side of the Channel.

“I don’t think we should give those politicians any excuse to do that. If we stay in a reformed EU, you know what you get – a border in Calais and vital information about criminals and terrorists travelling around Europe.”

Eurosceptic MPs including Liam Fox, the former defence secretary, and David Davis, a former shadow home secretary, criticised Mr Cameron’s comments. Mr Fox said he was “sad and disappointed”. Britain’s border arrangements had “nothing to do” with membership of the European Union.

Eurosceptic Cabinet ministers said Mr Cameron’s comments highlighted how “unfair” it was that the Prime Minister was free to speak in favour of Britain remaining in the EU while they were barred from speaking out until after a deal was secured.

Earlier Rob Whiteman, the former chief executive of the UK Border Agency, said the number of people claiming asylum in this country could rise from 30,000 to 50,000 a year if Britain left the EU.

However John Vine, the UK’s former chief inspector of borders and immigration, told the BBC Radio 4’s World at

One he did not think Britain’s exit would lead to an immediate collapse in cross-border arrangements with France.

David Cameron will attempt to secure an improved EU renegotiation deal this week after it was heavily criticised. British negotiators are pushing to strengthen the “emergency brake” on paying benefits to EU workers.