For polling anoraks one of the great joys of each new survey is being able to look at the detailed data. Quite often you can pick up trends and other findings that have not been included in the newspaper reports.

As a good example the table is a snapshot from the detailed data of the January poll for the Guardian which has just been published by ICM. It shows the cross-voting and changes when the named leader question was put. This, it will be recalled asks “If at the next election the Conservatives are led by David Cameron, Gordon Brown leads Labour and Ming Campbell leads the Liberal Democrats, how would you vote?”

So 96% of those who said they were voting Tory on the main voting intention question replied that they were staying with the party; whereas 83% of Labour supporters said their vote would be unchanged with Gordon Brown and the Lib Dems retained just 71% with Ming Campbell.

The Lib Dems pick up 5% of the Labour vote but see 12% of their support switch when the leaders names are included. The Tories, meanwhile pick up 9% of the Lib Dems supporters and 3% of the Labour ones.

These numbers are, of course small, but the movements are broadly in line with what has happened whenever ICM has asked this question over the past year.

Mike Smithson