The government has pledged to "argue Britain's corner" in the European Union, as Austria takes over the presidency from the UK.
Ministers have defended the UK's presidency
Europe Minister Douglas Alexander insisted "real progress" had been made during the UK's difficult six-month term, which ended in a budget deal.
Vienna has promised to push ahead with proposals for a Euro-tax to raise cash.
Mr Alexander said Britain remained opposed to the idea but conceded it would form part of discussions in 2008.
He told the BBC: "We are very clear as to where our national interest stands.
"We were very clear during the presidency that our obligation... was to seek consensus, but that that was a consensus that would necessarily and appropriately include Britain's national interest.
"Now that we won't be the presidency, have no fear that we will continue to argue Britain's corner within the European Union."
The UK took over heading the EU after the rejection of the proposed constitution by French and Dutch voters.
Mr Alexander said that as well as the budget deal, the UK had achieved a "genuinely historic decision" to open accession talks with Turkey.
President Fischer, who assumed the EU presidency on Sunday, said the constitution remains a good idea but the referendum results meant an alternative may have to be found.
And he said there were "good reasons" for a European tax.
"I know well it will be difficult to reach agreement. But if the European Union would have its own revenues it would be easier to negotiate the budget.
"We shall see how far we can go and how successful we can be."
Mr Alexander said he did not consider European taxation to be the right way forward.
But it would form part of budget review talks in 2008, secured by Tony Blair as part of the deal.
Liberal Democrat foreign affairs spokesman Sir Menzies Campbell said Britain's
"relative failure" meant Austria had much to do, to combat introspection and division.