Smaller museums rely on the rumour that every picture is nailed to the wall and alarmed

Alexandra Smith, Art Loss Register

French police said that Ms Breitwieser also dumped antique vases, weapons and musical instruments in the Rhine-Rh�ne canal.

Stephane Breitwieser, 31, accumulated a collection of 172 artefacts, including chinaware, pictures and statuettes, over seven years.

Breitwieser, currently in prison, stole the works in the years after 1995, travelling across Europe to work as a restaurant waiter in different cities.

With his girlfriend Catherine Kleinklauss he visited regional museums and smaller collections where security was less tight.

Breitwieser appears to have stolen works from museums in France, Switzerland, the Netherlands, Germany, Austria and Belgium.

Arrested

He took a 17th Century violin from the museum of musical instruments in Basel in Switzerland in 1996, and in 1999 he took Two Men by Antoine Watteau from the Museum of Montpellier, southern France.

He stored all the works in his mother's house in Strasbourg, eastern France.

He was eventually arrested in November 2001 after being seen stealing a bugle from a museum in Lucerne, Switzerland.

When his mother heard about the arrest she dumped many of the stolen artefacts in the canal - and later destroyed the paintings, forcing some of them into her waste disposal unit at home.

'Museum-quality'

Alexandra Smith, operation manager of stolen art trackers the Art Loss Register, told BBC News Online: "We've never heard of the destruction of works on this scale.

"The French police are quoting a value of 1.5bn euros, and when you are dealing with 60 to 70 museum-quality pieces that would be about right."

The destroyed masterpieces included Madeleine of France, Queen of Scotland, by the 16th Century artist Corneille de La Haye and Sleeping Shepherd by Fran�ois Boucher.

Mireille Breitwieser was taken into custody in Strasbourg on Tuesday, after Swiss police obtained permission to question her at her house.

She told police that she destroyed the paintings out of anger at her son.

The disaster has exposed the inadequacy of security arrangements at many regional collections in Europe.

"Smaller museums rely on the rumour that every picture is nailed to the wall and alarmed - but they're not, it simply costs too much for the smaller collections to do that," said Ms Smith.