Fancy seeing something truly terrifying in a glass case? Obiter recommends a trip to the Law Society Library. No, our librarians haven’t kidnapped Sir David Clementi for a Bentham-style exhibition. The exhibits under the glass include a 3.5-inch computer disc, a reel of magnetic tape, a Betamax cassette, 78 rpm records and some digital media cartridges of unknown format.

What they have in common, of course, is that they are all unreadable today. In fact we haven’t a clue what’s stored on some of the devices, though we think the 78s are prime minister Anthony Eden’s greatest hits.

The terrifying message is that by consigning all our most precious information to digital form, we are in danger of making history erasable at a stroke. The exhibition rubs the point in with a printed copy of Magna Carta – still legible after hundreds of years.

Old media have benefits apart from durability. Take parchment, used since time immemorial for recording important legal documents. Matthew Collins, an archaeologist at the University of York, has got in touch with research he is doing on the agricultural revolution in 18th century England.

He believes he can use dated parchment as a source of genetic information to track the emergence of modern breeds of sheep across the country.

While plenty of parchment is available, he has a problem: to be of value, he needs to know where parchment was sourced. Did, say, a lawyer in Norfolk procure parchment from local sheep, or did it all come from the 18th century equivalent of Viking Direct? He is keen to know if any firms still have account books dating back to the period, from which the information could be gleaned.

Possibly in 300 years’ time, archaeologists will be filleting memory sticks for clues about the 21st century, but Obiter somehow doubts they will be as rewarding.