IT sounds like the perfect plot for a Pink Panther film. A world-renowned museum is busily getting ready to put on a dazzling exhibition of fine art and jewellery.

But one key piece is missing.

A rare gold mechanical mouse, only one of four made, has been stolen and, though recovered, was at the centre of a court case brought about by a six-year police investigation of the antiques underworld.

However, Inspector Clouseau is nowhere to be seen, and the museum in question is the Bowes, at Barnard Castle, County Durham.

Staff at the 19th Century attraction are not amused either.

The £90,000 mouse was intended to be the centrepiece of a special exhibition, which will feature a number of old masters and some pieces that have not been exhibited for more than a century.

Instead, the little antique, which is gold-crusted and studded with tiny pearls, will remain in police custody until the outcome of the trial.

The museum is declining to comment on the case, but has assured the public the exhibition, Hidden Treasures, will begin as planned tomorrow - mouse or no mouse.

A spokesman for County Durham Police said their hands were tied because of the judicial system.

He said: "We would love to help the museum but we can't do much because the case is due to begin at Luton Crown Court in June.

"We can understand why they would want it as their centrepiece because it is obviously priceless and is a magnificent antique."