David Cameron yesterday suggested he could campaign for a vote to leave the EU if he fails to win major changes to Britain’s membership.

Seeking to contain a spiralling crisis after the defection of a second Tory MP to Ukip, the Prime Minister said reforms to immigration rules would be at the heart of his plan to negotiate looser ties with Brussels.

Mr Cameron said he was confident that other countries would agree concessions for the UK ahead of an in/out referendum, including an opt-out from the EU’s founding aim of ‘ever closer union’.

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Prime Minister David Cameron suggested he could campaign for a vote to leave the EU if he fails to win major changes to Britain’s membership. It came during an appearance on BBC’s Andrew Marr programme (above)

He said reforms to immigration rules would be at the heart of his plan to negotiate looser ties with Brussels

But he also gave the clearest signal yet he might recommend an EU exit if his renegotiation fails – a key demand of his Eurosceptic MPs.

‘If I thought that it wasn’t in Britain’s interests to be in the European Union I wouldn’t argue for us to be in it,’ Mr Cameron told the BBC’s Andrew Marr programme.

‘I am just a deeply patriotic politician and person. I do this job because I love my country, I care passionately about its future and I want it to be a strong, proud, self-governing independent nation.’

Reacting to Mark Reckless’s defection he said it was ‘counterproductive and senseless’.

He said the only choice facing voters at the next election was between a Conservative and Labour government.

He added that he would ensure rules on freedom of movement were reformed – suggesting that EU citizens working in Britain should be barred from sending child benefit back home, for instance – and that the right to work should also be restricted to countries whose economies have reached a certain level.

‘If you want to have a European referendum, if you want to have immigration controlled... there is only one option and that is to have a Conservative government after the next election,’ Mr Cameron said.

Mr Cameron (pictured) said he was confident that other countries would agree concessions for the UK ahead of an in/out referendum, including an opt-out from the European Union’s founding aim of ‘ever closer union’

ED MILIBAND ON COURSE TO WIN 'COMFORTABLE WORKING MAJORITY' IN '15 Ed Miliband is set to win a ‘comfortable working majority’ in 2015, pollster Lord Ashcroft said last night. The former Tory chairman said Labour could secure up to 37 per cent of the vote from core supporters and Lib Dem defectors. Ukip is likely to win Tory seats Thurrock and Thanet South, he added. A poll of 8,000 people found that more than one in four Tory voters in 2010 would now vote for another party. More than half would support Ukip. Lord Ashcroft said his polls put the Tories behind in 24 marginal seats – leaving them with fewer seats than Labour. Ed Miliband is set to win a ‘comfortable working majority’ in 2015, pollster Lord Ashcroft said last night Advertisement

Aides insisted the Prime Minister had not shifted stance on a referendum – but Eurosceptic MPs were convinced he had hardened his line.

And in a sign of the growing pressure on Mr Cameron over Europe, last night former defence secretary Liam Fox warned the Conservatives will lose the election unless they toughen up on immigration.

‘We had better have a workable narrative on immigration in the next six months or we are going to find it very difficult to win the next election,’ he told a fringe event.

Senior Tories are also telling the Prime Minister it is vital that the party halts the Ukip tide by defeating Mr Reckless in a by-election that is likely to be delayed until November.