The head of the Bundesbank appealed to Britain on Wednesday (23 July) to stay in the European Union, saying membership of the bloc had given the country an economic lift and posed little threat to London.

In a speech to business people and bankers in central London, Jens Weidmann broke the central bank's traditional silence on political questions, saying the European Union would benefit if Britain "continues to make its voice heard".

"The EU is stronger today because of Britain's contribution to it," Weidmann said, adding that the country's trade with EU neighbours had been boosted by more than half because of its membership of the bloc.

"As much as the UK gains from being part of the EU, so the EU gains from having the UK as a member," he said.

Weidmann's comments underscore the growing sense of nervousness about the possibility of Britain dropping out of the group of 28 countries that share common rules and club together to negotiate on issues such as trade.

While noting former British Prime Minister Margaret Thatcher's original Eurosceptic warning about the European Union, Weidmann sought to calm fears about a federal-style Europe, saying more centralisation of power was not necessary.

"Improving the workings of the European Union does not automatically require stronger centralisation," he said.

The remarks were in a similar vein to those made by Germany's finance minister, Wolfgang Schäuble.

Yet Weidmann's comments, coming from one of the most prominent central bankers in the eurozone, will have little impact on the debate in Britain, which wishes not only to stay outside the euro but also to change its terms of EU membership.

British Prime Minister David Cameron has promised to renegotiate these terms and hold an "in-out" referendum if re-elected in 2015, raising fears the world's sixth-largest economy could quit the club it joined in 1973.

Amid rising anti-EU rhetoric across Britain, relations between London and its European neighbours are already deteriorating. Cameron was recently isolated among his EU peers, for instance, in his attempt to derail Jean-Claude Juncker's bid to become president of the European Commission.

The situation worries many in the City of London, the financial centre that accounts for roughly one-tenth of the British economy, because it would lose out were trading to move to Frankfurt or elsewhere.

Weidmann said Britain's financial sector "stands to gain from dismantling the existing barriers to cross-border trade"