Gordon Brown, the UK prime minister, was facing growing pressure to extend the guarantees on British savers’ bank deposits after Ireland promised to underwrite the debts and savings accounts of its six largest lenders in a desperate bid to restore investor confidence in the ailing sector.

The Irish government’s emergency move was agreed by ministers and bank executives at a late-night meeting on Monday amid concerns about a run on an Anglo-Irish bank and raised the stakes in the state intervention sweeping Europe’s banking sector.