ONE minute he was marvelling at the rich fish and plant life, while the next he was squinting into a clutch of bright torches attached to five anxious police officers.

Diver Paul Homer had inadvertently sparked a major police security alert while diving under Bournemouth Pier. Up on the pier and promenade the 35-year-old noticed lots more officers with flashlights scouring the waters for him.

He was questioned on the spot, his gear and van searched, before being taken to Bournemouth Police Station for further inquiries.

Police also roused his elderly mum from her sleep at the family's Highcliffe home so that she could confirm his identity.

Officers are on full alert across the town in readiness for the Labour Party conference in Bournemouth next month. Continuing terrorist atrocities around the world have reinforced the need for top-level security, not only for Tony Blair and members of his government, but also for residents and visitors to the town.

Only hours before Paul embarked on his evening exploration under the pier, a bomb had exploded at the UN headquarters in Baghdad killing more than 20 people.

Ironically Paul, of Cranemoor Gardens, has already had his background details checked by police because of his part-time work as a Home Office contractor installing security systems into private homes.

"I don't normally dive under Bournemouth Pier, Boscombe is my favourite," he said. "I'd just finished doing a circuit between the pier's legs, looking at the crabs and bass, when I surfaced. Coppers were stood there waiting for me. I didn't take it very seriously because I knew I hadn't done anything wrong."

Paul doesn't belong to a local dive club, which he says police thought strange, but is a member of PADI (Professional Association of Diving Instructors).

"I'm mad for diving and do it every other day," he said. "In May I was diving off Orkney among the scuttled German fleet from the First World War. I love diving old wrecks."

He claims he finally left the police station after midnight and received a call the following day from an officer saying they weren't taking matters further.

"I think it's quite funny, all this," he said. "It must have cost them thousands."

Supt Geoff Watts, security co-ordinator for the Labour Party Conference, said: "The security of the public is paramount and Dorset Police is grateful for the alertness of a member of public who reported seeing a man diving under the pier.

"The incident - and its successful conclusion - illustrates the effectiveness of Dorset Police security procedures. Even at this early stage ahead of the conference, Dorset Police and its partners such as Bournemouth council are vigilant and aware of the importance of security for people living and working in town, as well as visitors to the resort and conference delegates attending the event.

"The diver came out of the water and co-operated fully and attended the police station voluntarily."