07/10/2012 08:42 BST

Boris Johnson Preferred By Wide Margin To David Cameron, According To Observer Poll

Voters much prefer Boris Johnson to David Cameron, according to an opinion poll.

The survey Opinium for The Observer gave the London mayor a net +30% compared to -21% for the Prime Minister.

The wide gulf between the two old rivals is likely to intensify speculation about Mr Johnson's long-term leadership ambitions as Conservatives gather for their annual conference in Birmingham.

The poll also showed a strong pick-up in Ed Miliband's approval rating, which has risen to -10% following last week's Labour Party conference - his best showing in an Opinium poll.

Deputy Prime Minister Nick Clegg, however, continues to languish on -48%.

Overall Labour enjoyed only a small post-conference bounce, up two points on 41%, an 11 point lead over the Tories, who are up one point on 30%, with the Liberal Democrats on 9%.

Opinium surveyed 1,965 UK adults aged 18 and over online between October 2 and 4.