The opening salvos in Labour's election campaign have backfired badly and amount to the worst political PR push in living memory, former Tory chairman Lord Patten has said.

Interviewed in the House Magazine, Chris Patten also suggests the Tories won in 1992 because voters gave them the "benefit of the doubt".

The former Tory chairman and recent European commissioner lambastes Labour's election strategy.

While he is known as a consensual figure, and an admirer of Tony Blair, the newly ennobled peer takes direct aim at Labour's election strategy.

"I can't think of a government re-election campaign that has had a worse beginning," he says.

"Bringing back Alastair Campbell; the over-the-top thuggishness about Michael [Howard]; and the worst slogan in living memory - 'Forward not Backward'."

Right time

He explains why the Tories managed to overcome the political pundits and secure a fourth election victory in 1992 under his chairmanship.

"I think we won in 1992 for two reasons. First, because we had the benefit of the doubt and second because our narrative was more credible than Labour's," he says.

"The reason why we flatlined for 10 years is because we never recovered the benefit of the doubt; and have not had a story that connects all the dots, both in policy terms and aspirations."

Patten also suggests that the UK would commit a major political own goal if it voted against the European constitution in next year's referendum.

"The rest of Europe thinks the treaty is a spectacular triumph for British diplomacy; it exhales British Gaullism," he says.

"If the British gave the thumbs down to something denounced in France for being too British, there would be a few waves of surprise and hostility in Europe.

"If 24 vote 'yes' - even 23 - and we vote 'no', do we think we can easily go back to the rest and say 'OK, you have all given it the thumbs up, but we want to renegotiate'?

"What would be the impact on our standing in Europe? How much clout would we have?

"I can understand the UKIP argument for going out - though I think it crazy, when you look at the rise of China.

"This is not the time to leave a Christmas club, let alone the EU. But I don't understand the point in remaining members but with minimum influence."