Three teenagers from Chalfont St Peter are set to cross the English Channel in September to raise money for a “life-changing” expedition to Africa, as well as for charity.

Samantha Farnfield, Jamie Nottage and Llewelyn Woodman, all 16, are planning to swim 21 miles in 14 to 18 degree temperatures to help fund Samantha and Llewelyn’s charity World Challenge trip to Zambia, where they will work with villagers to improve living conditions, repair buildings, play sport with local children and take part in treks and camping trips designed to build resilience.

Jamie is hoping to raise money for charity.

The teens, who attend Chalfonts Community College in Narcot Lane, will start their trip in the dark in the early hours of September 15 and are hoping to complete the journey in 15 hours.

Samantha signed up for the expedition last year and enlisted the help of her two friends to raise funds for the trip.

She is no stranger to challenges, having taken part in a 10K swim when she was just 11 to raise money for the hospice her grandmother was in and, two years later, walking 50K from central London to Windsor for the same cause.

She said: “I have been swimming all my life – we are all really excited to have the opportunity to swim the channel.

“I am really looking forward to the expedition and helping local people there.”

Samantha, Jamie and Llewelyn are hoping to raise £5,000 each, of which £3,000 will be spent on the swim and the remaining money will go towards the expedition and to charity.

In between studying for their GCSEs, the three friends have been training in colder-than-usual waters since wetsuits are not allowed when swimming the channel.

Samantha added: “The average temperature is around 14 degrees so there is a real risk of hypothermia. We will be doing a lot of cold water training in local lakes and rivers.

“We won’t be the only ones out there and we don’t just mean a few others trying to swim the channel on the same day.

“It is the busiest shipping channel in the world – 600 tankers, 200 ferries and other sea vessels cross the Channel each day and they have the right of way. Swimmers have to swim around them.”

Her dad Nigel said their plans for the summer holidays included training in lakes “multiple times a week” as well as weekly visits to the coast and a night time swim to prepare them for their mammoth journey.

For more information or to donate, go to www.jlsswimthechannel.com.