But the pollster, Peter Kellner, says the prime minister just about remained an electoral asset.

BBC: Westminster

According to Peter Kellner of YouGov, a polling firm, this cost the Conservatives 43 seats in 2001.

ECONOMIST: Bagehot

But there is no reliable demographic data at this scale, says Peter Kellner of YouGov, a pollster, so the technical difficulties would be formidable.

ECONOMIST: Polls and elections

Peter Kellner of YouGov, a pollster, points out that when polled on values issues such as attitudes to bankers or to gay marriage, Conservative voters may split 60:40 and Labour voters 40:60.

ECONOMIST: Bagehot

The Environment, Food and Rural Affairs (at 2.30pm) gets the views of water companies on the water white paper and the Scottish Affairs Committee (at 2.30pm) hears from leading political academics including Vernon Bogdanor and John Curtice, plus pollster Peter Kellner, the Scotland referendum.

BBC: Week ahead in Parliament

But Peter Kellner of the UK's YouGov polling agency said that opposition to gay rights legislation tended to be forgotten as soon as it became law, citing the examples of the UK's 1967 decriminalization of homosexuality and the changing of the law in 2000 to equalize the age of consent for straight and gay sex to 16.

CNN: Opinion: Why the fuss about gay marriage?