A teenager is halfway through a 66-mile swim in his school pool, as he raises money for his PE teacher's brother.

Jack Stone, 14, is undertaking the challenge for the Motor Neurone Disease Association (MND), as part of a campaign started by Sarah Culliford, a PE teacher at the Royal Russell School in Coombe Lane, Croydon.

Miss Culliford's brother Andrew is dying from the disease, which causes slow paralysis of the body. Life expectancy is usually one to five years from diagnosis.

Miss Culliford has asked staff and pupils at the school to support MND, and to raise awareness of the fatal condition.

So far, more than a third of students and staff at the school have pledged their support by signing up to the Vanguard Challenge, a 66-mile trek from Newhaven in East Sussex to East Croydon along Vanguard Way.

But Jack, a keen swimmer, has instead decided to swim the equivalent distance in the Royal Russell School's pool.

In total, he will cover 4,224 lengths of the 25m long pool - a feat he is expecting to take more than 30 hours to complete.

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He is covering the distance using a number of different strokes - front crawl, breaststroke and backstroke - to avoid injury and to keep the swim interesting.

Jack, who has attended the school since the age of three, said: “I heard Andrew’s story and it really got to my heart.

“I wanted to do all I could to raise money and as I like swimming I thought it would be good to cover the 66 miles in the school pool."

Jack started his sponsored swim six weeks ago and has so far covered around half the distance.

He plans to swim the final three miles on the Sunday, June 16 - the last day of the Vanguard Challenge. Several other pupils will complete 66 lenghts of the pool that day.

Jack added: “It can be a bit lonely swimming on my own for long periods of time, so I’m really looking forward to finishing the distance with company in the pool."

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Deputy headmaster David Selby said: “Jack is an inspirational young man who immediately offered to swim 66 miles when we announced the Vanguard Challenge.

“We asked pupils and staff to push themselves for this cause and attempt something more than they’ve ever done before and Jack is certainly doing that.

"He is a strong swimmer but 66 miles and 33 hours of his time is a huge commitment from him.”

Jack’s younger sister Anna and several of her friends from Royal Russell Junior School are also raising funds and will be walking the last six miles of the Vanguard Way on June 16.

Jack is hoping to raise more than £300 with his swim.

To sponsor Jack or find out more, visit vanguardchallenge.co.uk