All we can say is that it will be terrific when they finally get through

Public Record Office

Jill Brassington, from the Public Record Office (PRO), which created the service, urged users to be patient and said its technicians were doing everything they could to sort out the problems.

"We knew that a previous live site launched in America about Ellis Island had experienced huge demand and so we scaled up when we launched our site.

"I don't think that there is much more we could have done to prepare. But it is a success story in terms of the number of people interested and all we can say is that it will be terrific when they finally get through."

However, in a bid to improve access to the site, the PRO's Ben Quinn later said the website had been taken offline at 1330 GMT, while technicians tried to further boost capacity.

"The site will be back online from around 1600GMT and hopefully things will have improved," he said.

Slice of life

The 1901 census for England and Wales provides a unique snapshot of Edwardian Britain, with information on 32 million citizens including the Queen Mother.

Those who were able to search for ancestors on Wednesday found out details about their lives including where they lived, their age and even their mental state.

The PRO says the online resource will be invaluable for people all over the world who want to trace their British forbears.

The Queen Mother was only one when the census was taken

Census material is only released after 100 years, so these are the first public census records of the 20th Century.

Sue Gibbons, from the Society of Genealogists, welcomed the launch of the census website, and said the amount of material now available online was revolutionising the way people could search for their ancestors.

She said: "The internet has enabled mothers at home with children to research their family trees and the census will make an enormous difference."

It is estimated there are about 100,000 websites dedicated to tracing family history.

Before the net, genealogists trawled through parish records, went to St Catherine's House in London for birth, marriage and death certificates and the PRO, also in the capital, for the census.