A pay freeze for 750,000 public sector high earners, including senior NHS managers, GPs, council chiefs and judges, has been announced by chancellor Alistair Darling.

The suggestion that senior civil servants should share the pain of the recession comes at the end of a three year pay deal.

Jonathan Baume, general secretary of the First Division Association union, said the average senior salary of £75,000 a year is “relatively modest for what are very demanding jobs”.

He added: “This suggests the public finances might be in a worse state than the government has so far been letting on.”

The announcement came on the eve of shadow chancellor George Osborne’s speech to the Conservative Party conference in Manchester, prompting suggestions that Labour is seeking to upstage him.