A former Downing Street economic adviser has accused the prime minister of being "gutless" over the European constitution.

Speaking yesterday, Derek Scott argued that the new agreement would "exacerbate Europe's economic failings and drag Britain down too".

"There was no strategic thinking at all," he said in a lecture to the anti-constitution Vote No Campaign.

"The government drifted into negotiating over specific details.

"This sort of horse trading is the way Whitehall always deals with Europe and reflects the view that the best Britain can do is to negotiate 'something it can live with'."