One reason why Labour strategists are confident that their party will win the next election is that it is the "least toxic" among voters. While a significant chunk of the electorate would never consider voting Conservative (most notably ethnic minorities, northerners and Scots), far fewer would never vote Labour.

That point is reinforced by a new poll from YouGov today showing that while 33% would never vote Conservative, far fewer (24%) would never vote Labour. The Tories' problem is greatest in Scotland, where 59% would never vote for them (they currently hold just one seat out of a possible 59) and in the north, where 39% would never vote for them (they hold 43 seats out of a possible 158).

Conservative MP Gavin Barwell notes that "modernisation is about reducing/reversing this gap" but that's a project Cameron, under the tutelage of Lynton Crosby, long abandoned. The Tories are fond of deriding Labour’s alleged "35 per cent strategy", under which a coalition of the party’s core supporters and Lib Dem defectors allow it to crawl over the electoral finish line – but few note the irony that the Tory leadership has now adopted its own version of this game plan. Under heavy fire from the Ukip insurgency, the party has retreated to its core territory of welfare, immigration and Europe.

To surpass Labour in 2015, the party needs to expand its appeal considerably among those groups that have shunned it at the past four elections: ethnic minorities, northerners, Scots and LGBT voters. With the exception of equal marriage, few visible efforts have been made to do so. In January of this year, Tory strategists briefed that Cameron was so concerned at how the issue of race was damaging support for the party that he would address it "head-on with a speech in the next two months". Yet seven months on, nothing has been heard. Instead, the party has further damaged its reputation with ethnic minorities through a series of demagogic stunts on immigration.

But interestingly, the Tories are only the third most toxic party. Thirty five per cent would never vote Lib Dem, while 43% would never vote UKIP. While many casually claim that voters will never make Ed Miliband prime minister, it is the Labour leader who is fishing in the largest pool.