It follows plans being put forward by the council's chief executive to save money.

The proposal to cut posts follows the council's announcement before Christmas that it had gone £8m over budget.

The authority was also labelled "weak" in a report by the Audit Commission.

Budget deficit

The planned staff reductions will be put before councillors next Tuesday at a cabinet meeting as a solution to reducing the budget deficit.

The council's chief executive, Peter Gould, proposes cutting 150 managerial posts and about 300 support staff.

It is estimated the cuts would save the council £13m a year.

A spokesperson for Mr Gould said: "These are illustrative savings with no specific proposals.

"They form part of a report which aims to transform us into an excellent council through a series of major changes."

Richard Carr, branch secretary of the county council branch of the public service union Unison, said the news was "staggering".

"How does the council think it can improve services by getting rid of the staff who provide the services," he said.