Now ICM shows double-digit Tory lead

While the 16 point Tory lead on Sunday provided big headlines and no doubt cheered up Conservatives across the country, I suspect even the most rabid Tory suspected in their heart that it was probably an outlier and that the lead would return to more normal levels in the next YouGov poll. The latest ICM poll however suggests there may indeed have been some sort of shift in public opinion.

The monthly ICM poll for the Guardian has topline voting intention figures, with changes from their poll conducted last week, of CON 42%(+2), LAB 29%(-2), LDEM 21%(+1). The poll was conducted between the 14th and 16th, so would have included David Cameron's speech to the Tory spring conference.

The Conservative lead of 13 points is the largest I can find looking back at ICM polls since 1987. While it's smaller than the 16 point lead the Tories enjoyed with YouGov at the weekend, this seems to be a pattern between ICM and YouGov recently - the higher levels of Lib Dem support reported by ICM are at the expense of the Tories. Whichever pollster is correct, they seem to be interpreting the same underlying position.

Asked about who they trust more with the economy, ICM found an 8 point lead for the Conservatives, 40% to 32%.

It appears that, for whatever reason, the budget has heralded a fall in confidence in Labour's economic management and a decisive switch towards the Conservatives. While we've got a couple of polls confirming it, what we can't tell is whether it will last at all. If it does we are in a new game - it's the sort of lead where David Cameron is going to stop facing questions about why he isn't doing better, and is instead going to end up facing more criticism from his own troops about why he isn't being bolder. Labour would start facing assumptions of their defeat in the media and itchy backbenchers with the minds focused by possible unemployment.

UPDATE: Tables now up on ICM's website here. The difference between the lead here and the lead in YouGov's poll was actually mostly down to ICM's topline adjustment for the "spiral of silence" - the theory that some people who say don't know are actually supporters of an unpopular party who are too bashful to admit it to the interviewer. While people still refer to this an as adjustment to make up for "shy Tories", for the past five years at least it's normally favoured "shy Labourites". This month ICM's unadjusted figures would have been CON 43%, LAB 28%, LDEM 21%.