Throwing his lot in with the pro-euro Britain in Europe campaign, Mr Livingstone said London, as Europe's financial centre, could not risk being marginalised in the 15-nation EU.

"I have to state extremely bluntly that I do not believe it and will not be bound by it."

Determined

Mr Livingstone warned: "If one side argues against membership of the common currency, and the other side remains silent, as has been known to occur in the past, the case for the euro will be lost by default.

"If supporters of the euro do not put the case for it, the public cannot be expected to understand their message by smoke signals or subtle hints contained in unattributable briefings by spin doctors."

But the London mayor pledged not to clash with Prime Minister Tony Blair over the single currency.

He said Mr Blair and his cabinet colleagues were "as determined as I am that the long-term future and prosperity of London and the whole of Britain are protected."

Mr Livingstone's comments come after Northern Ireland Secretary Peter Mandelson reportedly sparked a cabinet row by saying economic arguments alone would not convince the public of the benefits of joining the euro.

Financial centre

Mr Livingstone, who has been chosen to spearhead the London in Europe campaign, said its aim was to "make sure that Londoners understand the importance of Europe to London's future and the impact the euro could have on their lives."

"London needs a campaign to place it firmly at the centre of Europe, economically and politically," he added.

"I believe this is vital for the future of the UK's capital city both for its role in the UK's domestic economy and for its place as the financial centre of Europe."

However, he said he is "completely confident that at the appropriate time the prime minister will lead a referendum campaign in favour of euro membership".

He said he also believes the government is in "no doubt about whether or not to join the euro", but only when to make this public.

"I believe that any party that believes they can wait on this issue is making a crucial mistake.

"My independent judgement is that we cannot wait," he said.

Case for London

"The reason why the case is so pressing for London is simple.

"Already since I was elected as Mayor, London has suffered loss of crucial jobs, at Ford Dagenham, which, I believe, was directly attributable to Britain's non-membership of the euro."

"The longer we are outside the euro the more we put at risk London's position as the financial centre of Europe and the future prosperity of the city.

London must be allowed to thrive and as mayor I cannot allow the developments of trends that would consign it to a second class position."

'Selling out'

But shadow London minister Bernard Jenkin accused Mr Livingstone of "selling out" the capital for the "worthless" euro.

"He is using London's government as a Trojan horse for a so-called 'Europe of regions'," Mr Jenkin said.

"London should remain the capital city of our sovereign British nation, not become a `region' of a European superstate."