Turmoil in the financial sector will hit tax revenues, the Treasury said on Thursday. Yvette Cooper, chief secretary, said that “of course the global credit crunch is affecting the UK’s tax receipts from financial services and stamp duty”.

But calculating the scale of the damage is tricky since corporation tax is notoriously volatile. In recent weeks, Revenue & Customs has been asking tax advisers for their own estimates of how much corporate tax payments should be revised.