The chancellor has warned that taxes could be hiked if the downturn is prolonged.Alistair Darling said last night that revenue had collapsed because of the recession, which ministers are trying to beat by spending on projects in an effort to kick-start the economy. According to the Independent Darling will announce details of a £4bn loan package to help smaller business cope during the difficult trading conditions. 'People should be in no doubt that the government will take the decisions necessary to ensure sustainability in the medium term [and] to return borrowing and debt to a sustainable level - once these current shocks have worked through - just as we have in the past,' Darling said. Darling also confirmed the government is to abandon its 'golden rule' which controls borrowing in order to boost public spending. 'To apply these rules rigidly in today's changed conditions would be perverse. The combination of the global credit crisis and the surge in commodity prices is unprecedented,' he said.