While Britain uses the pound, not the common currency, and the country’s banks are strong, the rest of the European Union is its largest trading partner. In addition, British officials have become increasingly concerned since the country slipped into recession earlier this year…

“This may be the most dangerous moment since the crisis erupted two years ago,” said Nicholas Spiro, managing director of Spiro Sovereign Strategy in London.

A number of other central banks also have taken steps in recent weeks to try to stave off financial contagion.

Central banks are facing pressure to act in part because political authorities have not moved fast enough to contain the accelerating crisis.