There are now as many as 2,500 UK government websites, yet more than a quarter of public sector bodies still don't know how much their sites cost, according to a report from the Committee of Public Accounts.

Of the organisations that could provide cost data, 40 percent merely offered estimates. And only 16 percent have solid data about how well their sites are being used. The report estimates that the government spends around £208m a year on internet services.

The government has, however, embarked on a programme to rationalise its websites by closing almost 1,000 "unnecessary sites", the report said. Agencies plan to move most citizen and business facing internet services to two websites, Direct.gov.uk and businesslink.gov.uk by 2011.

The government has identified 951 websites that could be closed. Alan Bishop, chief executive of the Central Office of Information, said: "Of those, 551, 56 percent, are already scheduled for closure. So far, there have only been 26 agreed exceptions out of the 951 and they are mainly for the single, departmental, corporate websites which will continue on into the future."

Committee chairman Edward Leigh told parliament: "The government's enthusiastic embrace of this new world of web-delivered services is not matched by a commensurate level of understanding of what it is achieving through its websites, how effective they are or whether they represent value for money."

Leigh added: "The time has long passed for getting a firm grip on the growth of government websites which has been almost uncontrolled."