The online version of the 1901 census has been pulled from the internet after BT warned that the system could not cope with the enormous demand for access.

BT, the internet service provider responsible for hosting the census website, revealed yesterday that it had advised the public record office to pull the plug when more than 7m people tried to access the service at the same time after its widely trumpeted launch last week.

The website, offering access for the first time to the details of more than 32m Edwardians, has been suspended for a week while the public record office and its technical advisers, Qinetiq - formerly part of the government's defence evaluation and research agency - attempt to increase its capacity.

The site was designed to handle a daily 1.2m visitors, spaced evenly throughout the day.

"We advised them to take down the site because it was not robust enough," a BT spokeswoman said yesterday. "When you have millions of people worldwide trying to get into the same internet space at the same time, that is going to create problems for the rest of the net."

The problems have been hugely embarrassing for the public record office, which has been criticised for generating so much publicity to accompany the launch before demand for the site had been gauged.

There have also been claims that geneaology and technology experts warned before the launch that the website would struggle to cope with the enormous demand from enthusiasts attempting to trace their family history.

Genealogy is now second only to pornography in popularity on the internet.

A public record office spokeswoman said: "The site remains unable to meet continuing levels of demand. The PRO has agreed with Qinetiq's technical team to close internet access to the site for one week for enhancements to take place."