Lloyd Scott practises his diving technique at a pool in Scotland

Lloyd Scott, 41, who set a world record for the slowest marathon time earlier this year, has entered the Loch Ness Marathon.

But he aims to become the first person to cover the 26-mile 385-yard distance under water - by plunging into the icy waters of the Loch.

Mr Scott said: "It will be quite dangerous. Aside from meeting the Loch Ness monster, the banks of the Loch are very very steep and it will be very, very cold.

"If I do meet Nessie, I'm not sure who will be more scared, the monster or myself.

"I've been told that the big copper helmet could give quite a big headbutt to the monster so it will be quite nice to make his acquaintance."

Scott took five days to run the New York marathon

The father-of-three from Rainham, Essex, was training on Wednesday for the event on 28 September at a diving pool in Fort William in the Highlands.

For the challenge, an eight-man team in a special boat with GPS technology will feed Mr Scott with oxygen from the surface via a pipe and record his progress.

The former chronic myeloid leukaemia sufferer began running marathons for charity after he was given a life-saving bone marrow transplant in 1989.

Mr Scott has completed the London and Edinburgh marathons this year wearing his 130 lb diving outfit.