German Foreign Minister Guido Westerwelle promised to mend fences with Britain on Monday after a divisive EU summit to save the euro zone left the island nation isolated in Europe.

I am here to show you that we are willing to build bridges over troubled water, Westerwelle told reporters at a joint press conference with British Foreign Secretary William Hague in London.

Relations between Britain and its European Union partners, particularly France, soured when Prime Minister David Cameron refused to sign a European deal designed to help solve the debt crisis after failing to win safeguards for the City of London.

But Westerwelle said on Monday that Europe had no hidden agenda against the City, a clear message to those who fear Britain's prized financial services sector could be at risk from EU countries that blame weak regulation and the market-friendly Anglo-Saxon model for the region's economic malaise.

We understand that we have mutual interests in a European common future, Westerwelle said. For Germany, the United Kingdom is an indispensable partner in the European Union.

Cameron's veto on December 9 raised concerns that London could be sidelined by the EU's 26 other members, or begin to slide out of the bloc altogether.

The German foreign minister's conciliatory tone was further evidence of Berlin's efforts to cool tempers over an issue that has caused tension between London and Paris in particular.

Britain's euro sceptic press joined MPs from the ruling Conservative Party in lauding Cameron's bulldog spirit after the veto, while France's prime minister and finance minister said France had more claim to a AAA credit rating than Britain.

Even Britain's deputy prime minister, Nick Clegg, a fervent pro-European, told French Prime Minister Francois Fillon that France's criticism of Britain was simply unacceptable.

Since the summit, both German Chancellor Angela Merkel and Cameron have stressed Britain's place as a key partner in Europe and Britain has also been invited to attend talks on the fiscal pact with the other 26 EU members who did sign up.

Some analysts argued that euro zone nations have used the row over Cameron's opt-out as cover to divert attention from their own faltering efforts to solve the euro zone crisis.

But economists have also warned that such divisions between EU members could mushroom as dismal economic conditions and the ongoing crisis tempt countries to champion national interests in order to protect themselves from the worst of the downturn.

(Reporting by Mohammed Abbas; Additional reporting by Adrian Croft; Editing by Ben Harding)