New polling suggests Labour's lead over the Conservatives is dwindling, raising the prospect of a possible Conservative majority at the next election.
A YouGov survey published this morning puts Labour just seven points ahead, on 42% to the Conservatives' 35%.
The poll follows two surveys this week showing limited support for the opposition. ICM put the Tories eight points behind and Populus put them just five points behind.
A Mail on Sunday report into a meeting of Tory Cabinet figures this week said David Cameron's strategy director, Andrew Cooper, believes Labour only has a six-point lead, with the Tories on 34%.
Tory strategists accept Ed Miliband's 'one nation' speech improved his personal ratings but think it only had a minimal impact on party backing, outside of consolidating pre-existing Labour support.
Recent Ipsos-MORI polling paints a more worrying picture for the Conservatives, after it found they were the most unliked party in British politics.
Sixty per cent of people say they dislike Tories, compared to just 35% saying they like them. The numbers compare unfavourably to the Liberal Democrats, who are disliked by 52% of the public and liked by 40%.
Labour was in positive territory, with 42% disliking the party and 51% liking it.
The figures suggest the Tories are still susceptible to a strategic voting environment, in which a segment of the population votes for whichever party has the best chance of keeping them out of power in that constituency.