Gordon Brown's "deep clean" policy to rid hospitals of lethal superbugs was branded an expensive failure after it was revealed that most health trusts had failed to carry out the procedure properly.

The Prime Minister ordered a £57m clean-up of 1,500 NHS hospitals in England last autumn, in an attempt to halt the rise of hospital-acquired infections including MRSA and Clostridium difficile (C. diff).

A survey of 200 hospitals showed that 85 per cent failed to use hydrogen peroxide vapour in their deep clean. Twenty of the 128 trusts that responded admitted that they did not use chlorine. Both cleaning procedures were recommended by the watchdog Health Protection Agency.

Figures released last month showed that the number of deaths from C. diff in English and Welsh hospitals has quadrupled in five years.

The Conservatives said the findings called into question the effectiveness of the deep clean.