The referendum question the UK may use if a vote is held on joining the euro has been published by the government.
Mr Brown will examine euro case next year
The question, revealed in the government's draft euro referendum bill, is: "Should the United Kingdom adopt the euro as its currency?"
Gordon Brown announced the paving bill in his pre-Budget report speech to MPs.
Downing Street on Thursday played down suggestions that the bill meant Tony Blair wanted a referendum on the same day as a general election.
The chancellor announced in June that the UK had yet to meet his five economic tests for joining the single currency.
The government says the new bill gives "maximum flexibility" over holding a referendum if the tests are passed.
Ian Davidson, chairman of Labour Against the Euro, said the bill included a
clause specifically stating that a euro vote could be combined with an
The five tests
Convergence with eurozone
Enough flexibility to adapt
Impact on jobs
Impact on financial services
Impact on foreign investment
The MP warned: "Plans to hold a euro referendum on the same day as a general
election are another sign of desperation by the euro enthusiasts.
"In their zeal to bounce Britain into the euro, they are willing to place at risk Labour seats and votes.
"A Labour Party seeking re-election would be deeply divided in a referendum, while the Tories would be handed the bonus of a campaign in tune with the majority of British voters."
But Downing Street said the government's stance had not budged since Mr Blair was questioned about the idea in May.
He had told reporters: "I have never had the idea of holding a
referendum on the same day as the general election."
A Number 10 spokesman said: "The position has not changed. It is pretty
categorical in terms of ruling it out."
The timing of the draft bill's publication has prompted Conservatives to accuse ministers of trying use the diversion of the pre-Budget report on Wednesday to hide the "controversial" wording of the referendum.
Tory constitutional affairs spokesman Alan Duncan said: "The government are back to their old tricks of trying to 'bury bad news'.
"The proposed referendum question breaches Electoral Commission guidelines on fair wording. It makes no mention that the pound would be replaced if people vote 'yes'.
"A fair question would make clear the implications for our existing national currency.
"The government are using sleight of hand to hide a euro referendum fix."
Mr Brown has said he will reveal in his Budget next year whether he thinks there is a case for another assessment of possible UK-membership of the euro according to his five economic tests.
In his statement on the single currency to MPs in June, Mr Brown said four of the five tests had yet to be met - the one relating to financial services being the only one to get the chancellor's approval.
But he said progress on passing two of the tests - on economic flexibility and convergence with the eurozone - would lead to the remaining two tests being satisfied.
The Department for Constitutional Affairs said the question had been drafted using Electoral Commission guidelines.
The Commission - which has a statutory obligation to assess the question - will formally review it when the bill is introduced into Parliament.
That would only happen if the Treasury decided its convergence criteria had been met and the economic conditions were right for Britain to lose to the pound.
Cabinet and then Parliament would then have to approve the decision before it went out to the British people.