Nick Clegg will bid to re-engage Britain with EU partners in the wake of David Cameron's Brussels treaty veto today when he hosts a summit of liberal allies from across Europe.
Among those due to attend are Dutch prime minister Mark Rutte, Olli Rehn, the European Commissioner for economic and monetary affairs, and German economy minister Philipp Roesler.
Clegg said it would set out "an ambitious agenda for reform" to promote economic growth ahead of the next EU summit at a "vital point" in the EU's history.
Aides said the senior politicians, including UK cabinet ministers, would focus on growth and the economy but debate seems certain also to focus on Britain's future role in Europe.
The coalition was rocked when David Cameron refused to sign up to a new EU-wide fiscal treaty in December, leaving the UK isolated in a manner Clegg warned was "bad for Britain".
He told Tory eurosceptics at the time he would not allow any further retreat to the margins and would instead "redouble our efforts" to fully re-engage.
Speaking ahead of today's meeting at Admiralty House, Clegg said: "Europe is at a vital point in its history and the crucial thing for us to do is concentrate on economic growth.
"That's why I'm hosting a meeting of my Liberal colleagues from parties in government across Europe to focus on the only credible path out of the current crisis, creating jobs and boosting competitiveness.
"We will be using this opportunity to set out an ambitious agenda for reform which will help set the stage for the discussions at the next European Summit."
Yesterday Cameron sought to play down concerns Britain would end up excluded from decisions affecting the single market under a new treaty being thrashed out in Brussels.
The latest draft of a fiscal accord designed to shore up the crisis-hit eurozone specifically talks about "deeper integration in the internal market".
It also suggests EU institutions would be involved in policing tough new deficit rules.
The prime minister said the treaty stated "very, very clearly" that it did not supersede existing EU treaties and so the UK interest was protected.
But shadow foreign secretary Douglas Alexander said the veto - which Cameron said was necessary to safeguard UK interests - appeared "more and more reckless".
Cameron also signalled that Britain would veto any attempt to introduce an EU-wide financial transaction tax unless it was being brought as a co-ordinated worldwide action.
Today's summit brings together ministers and commissioners from some of the 55 political parties from across the continent that belong to the European Liberal Democrat Party.