A third opinion poll in a week has suggested that the Tories have taken the lead over Labour - the first time this has been the case since 1992.

The Gallup poll in The Daily Telegraph puts the Tories on 40%, Labour on 35% and the Liberal Democrats on 16%.

The fieldwork was carried out over the past seven days, which included the worst of the fuel crisis and the row over whether Tony Blair and Gordon Brown had told the whole truth over Bernie Ecclestone's �1m donation to Labour.

The previous Gallup poll, published on 15 September, gave Labour 45%, the Tories 32% and the Lib Dems 16%.

Unlike other recent surveys showing a big Labour fall, the current poll shows most of the gains going one way - to the Tories - rather than being shared out among all the other parties.

Gallup questioned 1,006 people across the UK from 14-20 September.