In the week since the local elections, the Tory party has appeared anything but calm in its response to the UKIP surge. MPs have demanded an early EU referendum to give David Cameron a "mandate" to renegotiate Britain's membership (a referendum on a referendum, in other words), Jacob Rees-Mogg has called for a full-blown coalition, with Nigel Farage as Deputy Prime Minister (presumably after he's gone to the trouble of actually winning a seat) and Cameron has hurriedly brought Nadine Dorries back into the Conservative fold after rumours that she was on the verge of defecting to the Farageists.

Unfortunately for the Tories, then, today's YouGov poll will do little to calm their nerves. It puts them on a record low of 27 per cent (their worst rating not just since the election, but ever) and UKIP on a record high of 17 per cent, with 25 per cent of 2010 Conservative voters (excluding don't knows and wouldn't votes) telling the pollster that they would vote for the purple peril. The gap between the Tories and UKIP - ten points - is now smaller than the gap between them and Labour - 11 points. Labour's rating of 38 per cent is it worst since February 2012 but the even smaller Conservative share means Miliband would still win a majority of 108 on a uniform swing.

For Cameron, the risk between now and the election is that such polls will prompt Tory MPs to begin forming their own pacts with UKIP. While Farage has consistently said that Cameron is an insurmountable obstacle to a national arrangement, he has long made it clear that he is willing to consider local deals. As he told the Spectator last May, "What I do know is there are Conservative Associations up and down the country who think this could be a way forward… So all I would say to you is that in terms of co-operation or deals or anything in the future, firstly it’s some way off but secondly, I can see that there are associations thinking along the lines that if they approach us. Would I entertain and contemplate such ideas? Of course I would."

A string of mini UKIP-Tory pacts would force Cameron to choose whether to disown the candidates in question (triggering a Conservative split) or be seen to give in to Farage. With UKIP likely to enjoy another surge after next year's European elections, the dilemma will not go away. While Farage's party will still be lucky to win even one MP in 2015, it has the potential to prevent the Tories winning many more. At the last general election, with a UKIP vote share of just 3 per cent, there were 20 constituencies in which the UKIP vote exceeded the Labour majority (one shouldn't make the error of assuming that all those who supported the party would have backed the Tories in its absence, but many would have done). If UKIP starts to look as if it could determine whether the Tories remain the single largest party (an overall majority, always unlikely, now looks impossible), then the pressure for a rapprochement of the right will become overwhelming.