Changes to the machinery of government cost nearly £800m in the four years after 2005, and have not represented good value for money, the National Audit Office (NAO) has said.

In a strongly critical report, the NAO said central government has failed to identify the benefits it hopes to gain from the creation or reorganisation of departments, and changes too often had “vague objectives”.

In the five years since the last general election, several departments of state have been created – including the Ministry of Justice (MoJ) and Department for Energy and Climate Change (DECC) – and many more reorganised. Most controversially, the Department for Innovation, Universities and Skills (DIUS), set up by Gordon Brown in June 2007, was folded just two years later.

In all, the report said there had been more than 90 reorganisations of central government departments and their arms-length bodies between the election in May 2005 and June 2009.

Of the reorganisations examined by the NAO during that period, it put the total cost at £780m - an average of £15m for each reorganisation, and the equivalent of almost £200m a year.

The auditors point out that since 1980, 25 central departments have been created in the UK – and 13 of them no longer exist. In the US, where such changes are much more constitutionally restricted, only two departments have been created in the same period.

“Overall, the value-for-money picture is unsatisfactory and the costs are far from negligible," the report states.

NAO head Amyas Morse said “UK central government machinery is in a constant state of change.”

“We believe a more deliberate and carefully planned process makes sense before such costs are incurred, and would also like to see a slowdown in the rate of change," Morse added.

Public accounts committee chair Edward Leigh said: “Designers of logos and makers of nameplates have had much reason to be grateful for central government’s passion for constantly reorganising.”

He added: “It is hard to believe that this better serves the interests of the public than a deliberate and carefully planned process demonstrating that reorganisations make sense in terms of cost-effective delivery of services.”

A Cabinet Office spokesperson noted that 85 per cent of the costs highlighted by the report were as a result of changes to arms-length bodies. "We have set out a clear programme of cuts and reforms to these bodies, making it more difficult to set them up and ensuring there are plans for them to be abolished when their purpose has been served,” they added.

Speaking to Civil Service World earlier this year, former business department permanent secretary Sir Brian Bender – who oversaw several high-profile reorganisations – said such changes happened “too frequently and [are] potentially disruptive and costly”.