An ITV and Social Market Foundation survey reveals that Labour MPs are more divided than the Tories on the question of UK membership of the single currency.

Eighty one per cent of Conservative MPs stand shoulder to shoulder with Iain Duncan Smith over his sceptical position, with only 16 per cent in favour. On the government backbenches 23 per cent oppose joining the euro with 73 per cent backing membership of the single currency.

The Fabians will today call on the government to stop "prevaricating" on the euro and to launch a "grown up" debate on the issue.