There's a fascinating new Reuters/Ipsos MORI poll out which shows that voters in the key marginals rate Gordon Brown more highly than David Cameron.
As the graphs below show, marginal voters believe that Brown best understands the problems facing Britain and the world, and that he has a better understanding than Cameron and Nick Clegg of policy detail. What's more, he's rated as more capable and better in a crisis.
The findings contradict the received wisdom that while marginal voters still have reservations about the Conservative Party, they have been won over by Cameron's leadership.
Many Tories have only tolerated Cameron in the belief that he is an asset to the party. But if the Conservative leader starts to be seen as a hindrance rather than a help, that could all change.
The headline figures from the poll, which surveyed voters in the marginals Cameron must win to secure a majority, show the Tories on 38 per cent (up 1 point on two weeks ago), Labour unchanged on 41 per cent and the Lib Dems also unchanged on 38 per cent.
That represents a swing of 5.5 per cent to the Tories since the 2005 election, but Cameron needs a swing of 6.9 per cent nationally to win a majority in the Commons.
Reflecting the tightness of the polls, the proportion of voters who expect a hung parliament has increased from 55 per cent to 63 per cent.