Guards at the Louvre in Paris are to strike for more pay because of the stress of looking after Leonardo da Vinci's Mona Lisa.

The security guards have voted for industrial action in support of their claim for an extra £100 a month.

A spokesman for the guards said: "There are so many people all trying to take photos and wanting to see the picture that those who have Mona Lisa duty are under enormous stress. The 100 pounds a month (150 euros) is compensation."

They also want a lesser payment for guards on duty at the Venus de Milo, adding: "On a Sunday 65,000 people pass the paintings, it's hard work."

One third of the 180 guards voted in favour of a strike but with, the majority abstaining, it was enough to carry the vote.