It was meant to be a showcase for Britain's electronic prowess - a computer-based, multimedia version of the Domesday Book. But 16 years after it was created, the ￡2.5 million BBC Domesday Project has achieved an unexpected and unwelcome status: it is now unreadable.
The special computers developed to play the 12in video discs of text, photographs, maps and archive footage of British life are - quite simply - obsolete.
As a result, no one can access the reams of project information - equivalent to several sets of encyclopaedias - that were assembled about the state of the nation in 1986. By contrast, the original Domesday Book - an inventory of eleventh-century England compiled in 1086 by Norman monks - is in fine condition in the Public Record Office, Kew, and can be accessed by anyone who can read and has the right credentials. 'It is ironic, but the 15-year-old version is unreadable, while the ancient one is still perfectly usable,' said computer expert Paul Wheatley. 'We're lucky Shakespeare didn't write on an old PC.'
Nor is the problem a new one. A crisis in digital preservation now afflicts all developed countries. Databases recorded in old computer formats can no longer be accessed on new generation machines, while magnetic storage tapes and discs have physically decayed, ruining precious databases.
For millennia, men and women have used paper to create everything from the Dead Sea Scrolls to Neville Chamberlain's 'piece of paper from Herr Hitler'. In the past few decades, computers, scanners, cassettes, videos, CDs, minidiscs and floppy disks have been used to replace the written word. Yet in just a few short years these digital versions have started to degrade.
The space agency Nasa has already lost digital records sent back by its early probes, and in 1995 the US government come close to losing a vast chunk of national census data, thanks to the obsolescence of its data retrieval technology.
Betamax video players, 8in and 5in computer disks, and eight-track music cartridges have all become redundant, making it impossible to access records stored on them. Data stored on the 3in disks used in the pioneering Amstrad word-processor is now equally inaccessible.
Our digital heritage - only a few decades old - is already endangered, as broadcaster Loyd Grossman pointed out last week. 'Last year marked the 30th anniversary of email, but it is salutary that we do not have the first email message and no knowledge of its contents,' he said at the launch of the Digital Preservation Coalition. Saving Domesday Project is viewed as one of the coalition's top priorities.
It was to be the mother of all time capsules, filled with images and sounds defining life in Britain in 1986 - when hill farmers struggled to cope with Chernobyl nuclear fallout, Maradona beat England with the 'hand of God', and Michael Heseltine resigned from the Cabinet over the Westland affair.
Thousands of schoolchildren helped record festivals, events and details of ordinary life, which were stored on 12-inch laser discs.
They contained more than 250,000 place names, 25,000 maps, 50,000 pictures, 3,000 data sets, 60 minutes of moving pictures, and an unknown number of words. Around a million people contributed.The trouble was that the discs could only be viewed using a special BBC Micro computer, which cost ￡5,000 to buy. Few were purchased, and only a handful are left in existence. 'The information on this incredible historical object will soon disappear forever,' Grossman said last week.
In a bid to rescue the project, Paul Wheatley has begun work on Camileon, a program aimed at recovering the data on the Domesday discs. 'We have got a couple of rather scratchy pairs of discs, and we are confident we will eventually be able to read all their images, maps and text,' he said. 'Unfortunately, we don't know what we will do after that. We could store the data on desktop computers - but they are likely to become redundant in a few years.
'That means we have to find a way to emulate this data, in other words to turn into a form that can be used no matter what is the computer format of the future. That is the real goal of this project.'
It won't be an easy task. Jeff Rothenberg of the Rand Corporation, one of the world's experts on data preservation, points out: 'There is currently no demonstrably viable technical solution to this problem; yet if it is not solved, our increasingly digital heritage is in grave risk of being lost.'