Vince Cable has made it clear that he's available should a vacancy arise for the leadership of the Liberal Democrats, but what difference would he make to his party's election prospects? The latest Independent/ComRes survey asked voters this question and identified a significant Cable bounce.

With the Business Secretary as leader, support for the Lib Dems would rise to 18%, compared to 14% under Nick Clegg. On a uniform swing, that would leave the party with 39 of their 57 seats, compared with 23 under Clegg.

One should always be wary of polls showing that a political party would perform better under an alternative leader. Voters have a habit of favouring would-be leaders until the moment they're actually in charge. But with little evidence that Clegg can revive the Lib Dems' fortunes, the ComRes findings will concentrate the minds of his MPs. If the choice is between keeping their seats under Cable and losing them under Clegg, it would be surprising if they didn't rediscover their taste for regicide before the election.