The Bank of England would win new powers to mount covert rescues of troubled banks under options being considered by Alistair Darling, UK chancellor of the Exchequer, in the wake of the Northern Rock crisis.

Changes to the Takeover Code that would allow the authorities to arrange “white knight” deals quietly in a matter of days – rather than the minimum 60-day period required now – are among several ideas being looked at by the chancellor as part of an overhaul of financial regulation, the Financial Times understands.