Work is due to start next month (September) on cleaning probably the most famous piece of marble in the world - Michelangelo\'s David, seen at Galleria dell\'Academia in Italy by more than a million people every year.

The art world is divided, not for the first time, between those who want to wash the dirt off the sculpture and those who think the dirt is an integral part of its antiquity (it is 500 years old next year).

Preparations for the clean-up have taken 11 years, with every centimetre of the statue being digitally mapped for the smallest crack or blemish.

The plan is to wash the statue in water, but restorer Agnese Parronchi, who was employed to restore David, resigned in April, saying that only soft brushes should be used to clean David.

A petition has been signed by 40 art experts to stop the Galleria dell\'Accademia, in Florence, using their planned wet technique.