VALUABLE ivory carvings stolen from Bolton Museum in a daylight theft have been returned after being handed in by a mystery member of the public.

They were left on the counter at Bury Museum yesterday - with a note apologising and claiming that the whole affair was a security test.

The three Japanese Netsuke pieces, which are more than 100 years old, are thought to be worth around £2,000 each.

They were snatched on Monday when thieves unscrewed a display case at Bolton Museum where they were kept.

Today a Bolton Council spokesman said: "We're very pleased to have them back. They are apparently undamaged and will be going back on show."

Museum curator Steve Garland described the theft as "awful". He said: "The staff are very shocked, but it gives us a chance to learn and make improvements for the future.

"We will now be looking at how we operate security, the security of the items in the gallery, and the effectiveness of the CCTV system."

The council spokesman said it was important to strike a balance between providing security for the items and making them accessible to the public.

"After all, the point of a museum or gallery is to place items on show so that people can freely view them," he said.

The carvings were stolen despite a high-tech CCTV system and the presence of security staff who were patrolling the museum and art gallery in Le Mans Crescent. The carvings, which are between two and three inches high, were on show as part of the Water, Water art exhibition.

The pieces portray a fisherman with raised arms sitting next to a basket of fish; an ivory ball carved with dragonflies, butterflies, tortoises, frogs, snails and crabs; and two seated women with one holding an octopus by one of its tentacles.

The theft was not spotted until someone noticed the empty display case. The camera network covering the museum, which was installed just over a year ago, should be monitored continuously as part of Bolton Council's CCTV system.

Police are viewing camera footage to establish whether the thieves were caught on tape.

A council spokeswoman said security was constantly reviewed. She added: "Unfortunately this is not an isolated incident. A number of museums and galleries have suffered similarly in recent years."

Anyone with information about the latest theft is asked to call Greater Manchester Police on 0161 856 5593.