A leading pro-European pressure group has denied claims that it has shifted its public stance on the single currency in order to ensure government support.

Business for Sterling accused Britain in Europe of drastically toning down its previous support for the euro to fall in line with the prime minister's more conditional welcome for the single currency.

The anti-single currency group says BiE has radically changed its Website and public statements to persuade Tony Blair to front its cross-party campaign this Autumn.

It also points to the recent appointment of BiE Campaign Manager Simon Buckby, who masterminded Labour's last general election advertising campaign.

Nick Herbert of BfS: 'This will do their campaign great harm'

BfS Chief Executive Nick Herbert said that until a few weeks ago the group proudly proclaimed it was: "The campaign for British membership of the single currency."

But he says it has now downgraded that to saying it only wants to get the UK to keep its options open to join if the currency proves a success.

'Conditions have not been met'

Mr Buckby told BBC News Online that the UK should not join the euro if it flopped.

Simon Buckby: UK should not join the euro unless conditions are right

"Who would want to join an unsuccessful single currency?" he asked.

"At the moment we are not recommending that people should say, 'Let's join the single currency.' Conditions have not been met."

He declined to give reasons why voters should vote Yes in a referendum on signing up, saying that was not the campaign's job.

Website rewrite

However, at the start of July, BiE's Website described the group as "a unique organisation set up to inform the British people about the European single currency and convince them that Britain should join".

British Airways Chairman Lord Marshall chairs BiE

It quoted BiE chairman Lord Marshall, saying: "The single currency has now been successfully launched and, Britain is losing out because we are staying out."

That quote has been removed along with background documents extolling the euro's benefits.

BiE's Website now suggests that the currency has yet to prove itself.

BiE's Simon Buckby: 'We are campaigning for Britain to play a leading role in Europe'

It says the group represents the view that: "Britain gains greatly from its membership of the European Union and that we should maintain a credible option to join the single currency, if the economic conditions are met," it says.

One quote from Lord Marshall, that has survived, says: "Britain in Europe never has been wedded to the idea of rushing into the euro, regardless."

BiE 'not misleading public'

A BiE spokesman denied any shift in position. "We are not misleading the public," he said.

He added: "Simon's appointment draws a line under whatever went before. Whatever has gone before is now irrelevant."

But Mr Herbert insisted that the group had significantly changed its public stance.

Nick Herbert says his rivals have damaged their credibility

He said it now mirrored Mr Blair's line that the UK should only have a referendum if the single currency brings benefits to the 11 participating countries and the chancellor's economic conditions are met.

But Mr Herbert, said: "I think BiE is trying to pretend that they are something that they are not."

"I think that is misleading to the British public and business."

He rejected BiE's allegation that he was "making mischief" to try to conceal his own hidden agenda of working to get the UK to leave the European Union.

BfS wanted Britain to be in the EU, but not the euro, he said.

Blair 'has set conditions'

The euro had a bumpy ride on the money markets following its birth in January.

Mr Herbert, a former Conservative Party worker, says Labour has also had its fingers burnt by the Tory victory in the European elections.

Downing Street denies Tony Blair tried to influence BiE policy

He says that it is scared about the dangers of supporting the euro too overtly.

"I think it is clear that the prime minister in joining BiE set a number of conditions and one was that the campaign should not upset his wish to get the Labour government re-elected," he said.

BiE has, on several occasions postponed the start of its main campaign when Mr Blair will share a platform with senior pro-Europeans from other parties as well as union leaders and business figures.

Press reports have claimed Mr Blair delayed backing BiE as he did not want to be involved in a single-issue group and sought a wider campaign on the benefits of the EU.