They will find it very difficult to sell the euro to British workers if there is no social dimension in parallel

John Monks TUC leader

The criticism comes as European leaders head for Barcelona for a summit on European economic reform - an agenda on which Mr Blair has forged links with right-of-centre Mr Berlusconi.

Last month, the pair issued a joint statement to block further EU employment legislation.

Workers' warning

Mr Monks said Mr Blair had been "bloody stupid" to ally himself with Mr Berlusconi on workers' rights and warned that the unions were opposed to the views expressed in the statement.

"We've got a serious difference of opinion with them. We will not find it easy to sell the euro to British workers if there is no social dimension in parallel to that," he told The Times.

There is a great deal on our agenda which is actually going to improve workers' rights

Jack Straw Foreign Secretary

But Mr Blair's spokesman hit back: "He is not ashamed at all to work with whatever governments agree with our position.

"His commitment to flexible labour markets is in no doubt. It is whatever alliances we can make in Europe to achieve the objectives we can."

Foreign Secretary Jack Straw insisted that there was nothing on the summit agenda that would "erode" workers' rights and also stressed the importance of having "close relations" with all member states, no matter what their political leanings.

Good deal

The EU summit was taking forward the Lisbon reform agenda set by left-of-centre governments, including Britain, that would improve workers' rights, he said.

"There is a great deal on our agenda which is actually going to improve workers' rights," he told BBC Radio 4's Today programme.

"We have created a lot of jobs in the UK. We have got a lower unemployment rate, almost than any other European country and better than any of the major European countries," said Mr Straw.

"At the same time we have introduced the minimum wage, the working families tax credit and we have introduced trade union rights - the right to join a trade union and the right to recognition."

A Treasury spokesman said: "The approach we have taken domestically since 1997 is the best way to achieve social justice which is to get people into work."

In the Times article, Mr Monks insisted that the union link with Labour remained secure but said he was right to "sound an alert" about the direction the government was taking.

Unions 'clouted'

Mr Monks said the trade unions were "fed up with playing the role of stooges" to the prime minister.

The TUC leader likened the government-unions relationship to the comic double act of Eric Morecambe and Ernie Wise.

Union chief John Monks has met the Tories

"And little Ernie got clouted," Mr Monks told The Times.

Mr Monks is seen as a moderate figure within the trade union movement and is a strong backer of Britain joining the European single currency.

But workers' rights needed more protection before voters would support the euro, he warned.

Government critics fear Mr Blair, together with Italy and Spain, may argue against such moves in the drive for a more competitive European economy.

Welfare appeal

Mr Monks said he was a "strong European social democrat" and was worried Mr Blair was taking a different approach by taking the best of both Europe and America.

"I believe in workers' rights, welfare states, good public services allied to a lively market and that's what I want to see the prime minister and the British Government embrace, and not always looking for the balance and the triangulation."

Mr Monks said he was a strong admirer of Mr Blair in many ways but he worried that the wrong presentation was undermining reform of key public services like education and health.

He has continually urged ministers to give more details of their proposals.

"It's a sense of not knowing what's rhetoric, not knowing what's spin, and not knowing quite what's the reality," said Mr Monks.

But he is hopeful that phase is finishing as ministers will be judged on delivery, not spin.