Ringleader: Ian Davidson

Rebel Labour MPs have launched their own campaign against the European constitution.

With an internal party split threatening to undermine the government's bid to persuade the electorate of the Brussels treaty's merits, the backbenchers are set to anger the Labour leadership

Rebellion leader Ian Davidson said he would be gauging levels of support within Westminster at the first meeting of the "Labour against a superstate" on Monday.

The Glasgow Pollok MP has said he expects to have the backing of around 100 Labour colleagues in private.

But publicly only around 20 or 30 are expected to join the group.

Davidson has insisted he does not want to damage the general election campaign but was acting out of conscience in his opposition to the treaty signed by the prime minister last week.

"The constitution is another drive towards centralisation," he said.

The ringleader is calling for the referendum to be held after the general election and has promised to keep quiet until then as long as the "yes" campaign does the same.

However with europhiles keen for the campaign to begin as early as possible, this prospect appears unlikely.

Eurosceptic former Labour minister Frank Field said on Monday the EU could cope without a constitution.

"The show will go on as it is. If we are serious we know perfectly well the constitution won't go through. It will be vetoed in other countries as well as in this country," he told the BBC Radio 4 Today programme.

"What we now have, of course, is a whole group of states who have thrown off the shackles of communism and in no way are they going to agree to become sort of serfdoms in a single European state."