Significant parts of the core policy departments must move out of London if the latest round of civil service relocations is to succeed, a government adviser has said.

Ian Smith, author of a review of government relocations out of London and the South East published alongside the Budget, told Civil Service World this week that as well as saving money decentralisation should be embraced as an “ideological principle” because of its effect in regenerating deprived areas and bringing government closer to the people.

Smith praised Sir Michael Lyons’ 2004 report on decentralisation as the catalyst for the relocation of more than 20,000 posts outside London and the South East.

However, he added that “the game is now in central London,” where 60,000 of London’s 89,390 civil servants occupy offices in five post codes where the property cost per worker is around twice the national average.

Smith said that departmental targets were likely to follow in a spending review due to be carried out after the General Election.

He has recommended that the Treasury should make funding available to provide for the up-front costs of relocation, however he added that: “It’s up to them whether they can find the cash.”

In the report, entitled 'Relocation: transforming where and how government works', he advocates treating the government estate in Whitehall as a single campus that can be “managed down” over time.

Smith, the former chief executive of media group Reed Elsevier, was commissioned by Alistair Darling in December to produce the review.

The government has accepted his findings and the Chancellor pledged in his Budget speech to relocate 15,000 posts from London over the next five years, with civil service numbers in London to be reduced by a third over a 10-year period. It is hoped that the programme will produce annual savings of £160m after five years.