Question Time election debate: David Cameron has 'effectively resigned' after declaring EU referendum a 'red line' says top Lib Dem

Tim Farron said the PM had been 'foolish' to make EU referendum top priority for another coalition, unlike the 'smaller set of red lines' set out by Lib Dems

David Cameron said holding a EU referendum was a 'red line' for him in any coalition negotiations

David Cameron has effectively resigned as Prime Minister after declaring an EU referendum a "red line" in any coalition negotiations, a senior Liberal Democrat MP has said.

Tim Farron, the former Lib Dem president who has been tipped as a successor to Nick Clegg as leader, said Mr Cameron had been "foolish" to set out such a big red line, which he said contrasted with the "small number of red lines" set out by his party.

Asked during the Question Time leaders' debate which policies he would be prepared to compromise in coalition discussions, the the Prime Minister said: “The British people really do deserve a referendum on whether to stay in a reformed European Union or leave... I will not lead a government that doesn’t honour that pledge. That’s a red line.”

Mr Farron, speaking to The Independent after the debate, appeared delighted with Mr Cameron's new 'red line': "That’s him resigning on Friday. Cameron’s just resigned his leadership."

He added: "We’ve been very, very careful to set out a small number of red lines – less than last time around. Cameron has really foolishly picked one red line that 90 per cent of the electorate – whatever their views on Europe – most people think that it’s about 107th in their list of priorities.

"He’s either told us a big, big lie or he’s resigned – we’re in the last 7 days of Cameron’s premiership."

The latest red line to be outlined by Mr Clegg is a commitment to spend an extra £8 billion a year on the NHS by 2020.

This follows three other red lines set out this week. These include pledges to increase education spending in England from £49bn to £55.3bn over the next five years, raising the basic rate income tax threshold to £12,500 and holding a "stability budget" within the first 50 days of a new Parliament.

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