Government watchdog the National Audit Office (NAO) has issued guidelines for making public services available online following its investigation into the 1901 Census project.

The Census website was crippled at launch and not fully online until 11 months later.

"It is important that the wider public sector learns the lessons from this project," said Sir John Bourne, head of the NAO.

The Public Record Office, now the National Archives, put the 1901 census online on 2 January 2002. But the site attracted as many visitors in an hour as they had been expecting in a day, and quickly buckled under the demand.

After five days, during which the 1.2 million users per hour were receiving poor website performance, the site was taken down.

It was relaunched with limited access from August 2002, and full access on 21 November 2002. Since its restoration, traffic levels have been just 8,000 to 10,000 a day.

But the NAO concluded that the Public Record Office had taken the correct decision in engaging contractors QinetiQ to develop the website.

Since identifying and sorting out the initial problems, the service has generated some £4.5m in revenue and is on the way to being self-financing, as originally intended.

"The project to provide online access to the 1901 census was ambitious and, ultimately, successful," said Bourne.

The embarrassing collapse of the site sent out a warning not to cut corners during the initial implementation stages, according to analysts.

"The pressures of delivering these systems on time and to budget place huge demands on the project teams," said Tony Lock, chief analyst at market watcher Bloor Research.

"Quite often you see that it's the system testing and contingency planning that are the first items to be cut."

www.census.pro.gov.uk