David Cameron called on the government to offer to underwrite all new business lending as the Tories on Friday signalled an end to their bipartisan support for Gordon Brown’s handling of the banking crisis.

The Conservatives backed last month’s £37bn ($57bn) taxpayer-funded recapitalisation of the banks in the belief that it would help to save the real economy and restart lending to businesses, the Tory leader told a London event. “And on those tests, we must all agree that the bank recapitalisation is failing.”