A book thief who served a four-year jail sentence should have turned over a new leaf. Instead, he has been sent back to prison after targeting one of Britain's most distinguished libraries. The case highlights a little known, but widespread crime.

When William Jacques pilfered books from a London literary collection his punishment was far worse than a library fine. But as prosecutor Gino Connor put it: "We are not dealing with Penguin books."

Nicknamed the Tome Raider, William Jacques had form in library crime - having already served a four-year sentence for stealing books worth £1m in the late 1990s.

Despite his prison term, it seems Jacques could not give up his habit of lifting notable works of literature.

The 41-year-old has been sentenced to another jail term, of three-and-a-half years, after targeting the Royal Horticultural Society's Lindley library. Signing in under the false name of Santoro, he simply stuffed books under his jacket before marching out.

He escaped with rare volumes of Nouvelle Iconographie des Camellias, by Ambroise Verschaffelt, before a suspicious staff member alerted police.

But while his methods may not have been very hi-tech, few doubt Jacques' cunning and intelligence.

Cambridge-educated with an understanding of antiquarian books, Jacques started stealing distinguished works of literature by plundering the collection at his old university library.

Between October 1996 and May 1999, he stole about 500 extremely rare books and pamphlets from Cambridge, the British Library and London Library.

Many were then sold on through auction houses in the UK and abroad, netting him hundreds of thousands of pounds.

Jacques' actions came to light when one of the books he had stolen came before antiquarian book dealer Jolyon Hudson.

Mr Hudson was suspicious of the volume, which had a shadow on the cover where a library label might have been, a ripped page - as though an embossing mark had been removed, and an altered spine.

It's hardly the stuff of hardened criminals, but Mr Hudson, of Pickering & Chatto in London, says theft of valuable books remains a problem. This is despite many research libraries restricting viewing to members.

"There are people who get access to libraries and can cause a lot of damage. It's very difficult to stop," he says.

"[Jacques] is very adept at it. He seems to wheedle his way in and be very convincing."

Many thieves have profited by cutting maps or image plates from antiquarian books.

But for Mr Hudson, the act of damaging the books was as bad as the theft itself.

"It kills history... damaging books in such a way that you can't see the provenance," he says.

"If you tear Churchill's signature from a book, you have an old book and a piece of paper with a signature but no context to say that it belonged to Churchill and when."

Even if a bookseller becomes suspicious, without that context it is difficult to detect a stolen book, he says.

There is also a feeling among some book dealers that the crime is not treated seriously enough

"Imagine if somebody tore a signature off a Monet painting. Would people say that didn't matter?"

It's a mark of how widespread this sort of crime has become that last month, the International League of Antiquarian Booksellers set up a Stolen Book database.

The league encourages booksellers, libraries, museums, national governments and police to contribute details of stolen volumes, which can be checked by booksellers if they are suspicious about an offering.

In the UK, the Antiquarian Booksellers Association has evolved its "stolen book chain" - a system where dealers each phoned five contacts with a warning - into an e-mail theft bulletin.

Its president, Julian Rota, acknowledges that book theft - not just from libraries but also from booksellers - is widespread.

But he said people in the industry could do their bit.

From the BBC website