Title deeds - those big sheets of parchment covered with meticulous calligraphy - are the most abundant historical documents and one of the most neglected collectables.

People walk past them as they lie discarded in rummage boxes in book shops and markets, not knowing what they are. But ever since the Domesday land survey of 1086, the English household's most cherished possession, after the family Bible, has been the title deed, proof of ownership of buildings and land.

Until 1926, that is, when the new Land Registry was set up and they became junk. Some solicitors turfed them out of their strongrooms and made bonfires of them. Some deeds ended up as lampshades.

And some were collected. In the late Eighties I bought job lots of scores of them from the late George Jeffery's secondhand book barrows in Farringdon Road, East London. The price was pounds 1 each for Victorian, Regency, even 18th and 17th century specimens. It was nostalgia that drove me. The signing of the earlier deeds would have been ceremonial occasions, the parties to the sale or lease meeting in the baronial court before the Lord of the Manor's steward.

Apart from marriage, the covenant of which the deed was proof would have been the most solemn that a man or woman could undertake - assigning farms and fields, castles or cottages for years, a lifetime, or "for ever".

And are they now worth a fortune? Not at all. You can still pick them up for a quid each if you are lucky, although the going rate for a Victorian parchment deed is now anything between a fiver and a tenner.

I did try to sell some of mine, knocking on the doors of once-proud Victorian villas built in Pimlico in the 1860s, proferring the house's original deeds, signed and sealed by the builder, the landowner and the very first leaseholder. Some had interesting conditions written into them - prohibiting brothel-keeping, for example.

But, as often as not, the door would open a crack and I would be greeted by one of the multi-occupiers, unshaven, wearing a grubby vest, and eager to inform me that the rent had been paid and that I should sod off.

I nevertheless urge you to snap up title deeds whenever you spot them. Their value can only go up. The electronic age is turning handwritten documents into curios, handwritten parchments especially so. The true stories they reveal provide hours of fun, as collectors say, and their illuminated calligraphy is a joy in an increasingly cack-handed age.

Recently, there have been chunterings among academics that private possession of these unique historical records should be regarded with the same opprobrium as collecting antiquities - always a sign that things are worth hanging on to.

Moreover, I recently bumped into a dealer who specialises in title deeds, so their value must have increased sufficiently to make them commercially worthwhile. Michael Kashden, of Edgware, will sell a Victorian or Regency title deed for a tenner or so: "They're cheap for what they are. Think of the work involved in producing them."

Indeed, those scribes on high stools who decorated the word "Indenture" with lattices of fancy scrollwork worked on sheepskin soaked, stretched on frames and scalded (scraped smooth) in a way unchanged since the Conqueror's time.

When the untutored realise they have in their hands a centuries-old parchment manuscript, their minds tend to flip into Cor!-must-be-worth- a-fortune mode. "Some ask me whether they are reproductions," Mr Kashden says. "You couldn't possibly make reproductions at the price these originals are being offered."

The old parchments tell a yarn or two. Mr Kashden indicates a deed for the recovery of land, signed on vellum (calfskin) on behalf of Richard Cromwell in 1658, during his nine months as Lord Protector. A stroke of the pen, a dob of wax, and one John Davenport, gent, loses 17 messuages (dwelling houses), 156 acres of land, 100 acres of meadow, 200 acres of pasture and two acres of wood in Keyston and Bythorn, Huntingdonshire. The document is priced pounds 750.

Then there is a deed of 1348 signed by Edward III, giving land to a knight who had fought in the Hundred Years War. It has a three-and-a- half-inch green wax seal attached, showing the king's coronation in Westminster Abbey, and the words: "Witnessed by me in Calais in the 21st year of our reign in England and in France the 8th." Price? Mr Kashden won't part with it.

Michael Kashden, phone 0181-958 1018. `Old Title Deeds, A Guide For Local and Family Historians', by NW Alcock, Phillimore 1986 (pounds 13.95).