Who failed to switch on the alarm?

Often when I walk round museums I can't help speculating how many millions of pounds worth of paintings are in one room. Sometimes the sums are simply breathtaking. I've then speculated also about how much top-notch security must be involved in keeping those paintings safe. Inevitably I then marvel at the way in which, year after year, so many of the eminent museums around the world do a really excellent job of keeping our art heritage safe from thieves - and those greedy people who need to boost their self-esteem with some stolen art!

However apparently not much is kept safe if somebody fails to turn on the alarm system!

As the Musée d'Art Moderne de la Ville de Paris in Paris found out this morning when they discovered that a window was broken and five paintings by Picasso, Matisse and other great artists had been stolen - and the alarm had not gone off.

I was not surprised to find out that 90% of all art theft involves somebody on the inside of the museum.  After all if the technology all works then some sort of human failing is all that is left.

Le pigeon aux petit pois (Dove with Green Peas) (1911) by Picasso

The paintings, stolen overnight on Wednesday, are estimated to be worth just under 100m euros (£86m; $123m).

However, I was pleased to hear the man in charge of the Art Loss Register explaining that their real value lies in what those paintings represent in terms of explaining the development of the individual artists and of modern art in general.

I'd not come across the Art Loss Register before as a specific entity but was vaguely aware of their existence

The ALR is now the world’s largest private database of lost and stolen art, antiques and collectables. Its range of services includes item registration, search and recovery services to collectors, the art trade, insurers and worldwide law enforcement agencies. These services are efficiently delivered by employing state of the art IT technology and a team of specially trained professional art historians.

It was interesting to see on their website that they have been successful in aiding the recovery of items previously stolen

Highlights of this excellent and improving record have been:

• Paul Cezanne Still life with Fruit and a Jug Stolen 1978 Recovered 1999
• Edouard Manet Still life with Peaches Stolen 1977 Recovered 1997
• Pablo Picasso Woman in white reading a Book Stolen 1940 Recovered 2005

Let's hope the art stolen last night is also recovered.

This is a slideshow of the paintings which were stolen

These are links to articles commenting ion the theft

• Jonathan Jones / Guardian: The Paris art theft has robbed us of some truly great paintings
• Paris art theft: Experts puzzle over motives of 'unusual heist'
• Bloomberg - Picasso, Matisse Paintings Stolen From Paris Museum (Update4)
• BBC Hunt for modern art theft

Note: The Museum is not to be confused with the Musée National d'Art Moderne which is housed in the Centre Pompidou.  This one is for the City of Paris's modern at collection - not the national modern art collection.