Peter Mandelson has backed the chancellor's appeal for reform of the European economic and social model.
Gordon Brown on Thursday warned that the high level of unemployment across the continent shows Europe's economic system "is not working".
Writing in the Financial Times, the chancellor argued that "the time for debating European economic reform is over" and that "now is the time for action".
As Britain prepares to host a meeting of EU leaders on Europe's economic future, Brown makes it clear that he believes it is a "make-or-break summit".
And it must press home reforms of Europe's labour and capital markets, trade and macroeconomic policy, he says. "The change we need is quite fundamental."
Brown says Europe's growth rate this year of 1.2 per cent "is a wake-up call we cannot ignore". "An old model that leaves 20 million unemployed, 10 million of them for more than a year, is not working," he argued.
Progress
The article came ahead of the publication of a 7,000-word pamphlet the chancellor has written on Europe's economic future.
The chancellor later told MPs during Treasury questions that Britain was "directly affected by low growth in the European Union".
"Therefore it is not a source of celebration when countries who are neighbours of ours grow slowly, it is a source of worry and anxiety for the British economy."
He added: "We must produce policies in the European Union as a whole so that there is greater growth."
Brown said his priorities were to speed up creation of the single market, make progress in trade talks and reform the social model "so that instead of 20 million people being unemployed we get people back to work".
Fear
The chancellor received backing from Peter Mandelson, who said there was "a very strong case for economic and social reform" in Europe.
However the EU trade commissioner also cautioned that there were widespread public fears about the impact of reform.
"I think the problem, if I can put it in this way, is that the pressures of international economic change are seen by people throughout Europe in many cases not as an opportunity but as a threat," he told a committee of MPs on Thursday.
Mandelson said there is "a fear amongst people about global competition".
He added that there was not enough focus on "the emergence and growth of global markets in which we can trade and sell our goods and services in order to maintain the standard of living and quality of life which that we have got used to enjoying in Europe".
"We will only maintain those living standards and keep that quality of life - indeed sustain our social standards and environmental standards let alone the economic growth that we have experienced in the past and need to again - if we look to international markets," said the commissioner.
