The chancellor is said to be set to back British membership of the euro.

Gordon Brown is co-ordinating his actions with those of Tony Blair as the government moves closer to holding a referendum on the euro, according to reports.

Brown, whose position on the euro has been less clear than that of the more publicly enthusiastic prime minister, is said to have told his allies to talk up the likelihood of British membership before the next election

One Brownite minister told the Sunday Telegraph: "This is being coordinated by Number 10 and Number 11. Ministers who go on the record do so with the explicit approval of both Tony and Gordon."

Nigel Griffiths, the junior trade minister and ally of the chancellor, recently said it was his "hunch" that Britain would join the euro within two years.

While Brown publicly insists on a "rigorous" assessment of the government's five economic tests, his support for membership would be seen as a vital shift, bringing the prospects of a euro vote much closer.

The government has stepped up its pro-euro drive, with Tony Blair telling the BBC last week that if the five tests were passed it would be "overwhelmingly" in Britain's interests to join and a "betrayal" to stay out.

And Stephen Byers also added to sense of momentum when he disclosed that a referendum bill could follow this autumn's Queen's Speech ahead of a vote scheduled for next year.

Government polling is also reported to have revealed a narrowing gap between supporters of the euro and those opposed to Britain's membership.