The job remit of Britain's top senior civil servant is to be radically transformed in order for Tony Blair to fulfill his main aim of improving public services.

The new cabinet secretary and head of the home civil service - to be appointed following Sir Richard Wilson's retirement this summer - will be responsible for driving through the government's public service reforms, rather than merely being responsible for the collective cabinet system of government.

However, the new cabinet secretary will continue to sit by the prime minister's side at cabinet meetings and will remain in charge of the cabinet secretariat which serves ministers.

Sir Richard Wilson is now expected to consult with the existing permanent secretaries to sound out possible successors and listen to suggestions about the plans.