Leading trade unionists have urged the government to keep up the momentum towards British membership of the single currency.

In a booklet launched on Tuesday, the group Trade Unionists for Europe said that entry membership of the euro should follow swiftly after the government's five tests are met.

The unions called on the government to accept the case for an early referendum - warning that to delay would put jobs and British influence at risk.

However, the study also accepts that there should be changes to the way the European Union works.

It calls for more openness and a lifting of "the veil of secrecy behind which the Brussels bureaucracy works".

Some unions leaders are concerned that the requirements of the EU's stability and growth pact could force public spending cuts if deficits rise during economic slowdowns.

"Without a strong framework of employment and social rights the EU will fail to gain the support of its citizens," said the report.

Senior union leader John Edmonds also highlighted recent exchange rate movements as a further reason why Britain was moving closer to euro membership.

"The government must maintain the momentum towards UK entry into the eurozone. The exchange rate of the pound is at last moving in the right direction and Gordon Brown's five tests have been met," the GMB general secretary said.

"Gordon Brown should guarantee that his public spending plans are safe from any EU stability pact squeeze and give the green light to Britain joining the euro.

"People will vote yes provided they also see the EU adopting a positive social agenda so that industrial casualties do not become social outcasts."

The Trade Unionists for Europe organisation was set up in 2000 to promote the trade unionist agenda in Europe and the euro, and comprises representatives from Amicus, ISTC, GPMU, GMB, KFAT, PCS and Unifi.

Their push for euro membership comes amid suggestions that the war with Iraq will delay any referendum on joining the single currency.

And Britain's rift with France over Iraq has also been cited as a reason why the prime minister will not take on another big challenge while dealing with the issues of war and terrorism.