The snail Papillifera bidens is 1.1 cm long has a pinky-grey spindle shaped shell and hails from the Mediterranean where it is often found on old buildings. It has been found at two sites in the UK, Brownsea Island an Cliveden bothed owned by the National Trust.
It is thought that it came to the UK after the Victorians imported statues, rock and brickwork from the Mediterranean.
The snail was thought to have arrived at Cliveden on a balustrade from the Villa Borghese in Rome in 1896.
The Trust are now conducting an audit of its property to see if is found elsewhere, the snail could now be in other parts of the UK after stonework from stately home gardens were sold off and relocated elsewhere.