Just one percent of all British websites will be covered in a UK archive by next year unless laws are changed, warned the British Library.
Its UK Web Archive, which was officially launched today, contains just 6,000 of around 8 million UK websites.
According to the British Library, on average UK websites have a lifespan of between 44 and 75 days. It also said that at least 10 percent of all UK websites were either lost or replaced by new material every six months.
However, under the 2003 Legal Deposit Library Act the group needs to gain permission from the website owner before it can archive the site, which is slowing down the process dramatically.
"Throughout the project the Library has worked directly with copyright holders to capture and preserve more than 6,000 carefully selected websites, helping to avoid the creation of a 'digital black hole' in the nation's memory," said Dame Lynne Brindley, chief executive of the British Library.
However, Brindley added the group was "limited by the existing legal position" and, at the current rate, it would have collected just 1 percent of all free UK websites by 2011.
Websites already archived include high-street retailers Woolworths, which went into administration at the beginning of 2009, and Antony Gormley's fourth plinth project in Trafalgar Square.
Minister for culture and tourism Margaret Hodge said: "The British Library's UK Web Archive is a fascinating snapshot of the way this country uses the internet.
"In the years since the internet began to be a part of our lives, the amount of information we have been able to access is simply unparalleled. The range of subjects is enormous, and reflects the diverse society we live in today."
The Department of Culture Media and Sport is currently reviewing the Legal Deposit Library Act.