On the surface, the latest Reuters/Ipsos MORI political monitor should gladden Labour souls. Last month's poll put the Tories neck and neck with Labour on 40 per cent, but this month's gives Ed Miliband's party a 7-point lead. Labour is up 2 points to 42 per cent and the Tories are down 5 points to 35 per cent.

But dig deeper and some worrying trends emerge for the red team. Net satisfaction with Miliband, which stood at +1 last month, is back down to -8 (see graph below). More worryingly, just 17 per cent of voters believe the Labour leader is ready to be prime minister, compared to 69 per cent who believe he is not.

By contrast, 31 per cent of voters say Labour is ready to form the next government, a finding that will again give Miliband's critics cause to ask if the party could be performing better under an alternative leader.

Elsewhere, there's more evidence that voters share George Osborne's belief that the government is clearing up "Labour's mess". Asked who they will blame if the economy gets worse over the next 12 months, 22 per cent of respondents say the last Labour government but just 10 per cent say the Tories.

A total of 27 per cent would blame both the Tories and the Lib Dems but that's only 5 per cent more than would blame Labour. Given that the economy was growing at an annual rate of 4 per cent under Labour but has ground to a halt under Osborne, that's some achievement by the Conservatives. As Douglas Alexander recently lamented, Labour's marathon leadership contest allowed the coalition to define the terms of debate from the start.

Miliband's troubles, however, are as nothing compared to those of Nick Clegg. Net satisfaction with the Deputy PM has plummeted from -18 last month to -32 this month. For the first time, Clegg's approval rating is below that of the coalition. By contrast, net satisfaction with Cameron remains at -3, a poor rating but not terrible. Miliband, who has led Cameron in every MORI poll since January, is now behind the Prime Minister. Personal approval ratings are often a better long-term indicator of the next election result than voting intentions. Labour frequently led the Tories under Neil Kinnock, for instance, but Kinnock was never rated above John Major as a potential prime minister.

Can Labour defy history and win an election under an unpopular leader? That is the question some in the party will be asking today.