A sixth form student who swam the equivalent of the English Channel in Royston on Monday said it was his most difficult charity challenge to date – even tougher than his previous five-day sponsored fast.

Harry Barnes swam 1,324 lengths in 14 hours 55 minutes at Royston Leisure Centre, striking out at 6.10am and not finishing until 9.05pm.

The 18-year-old who lives in Buntingford said: “The first few hours were fine but then holding my neck up became painful and I slowed down - my friends showed up for a few hours and helped me carry on.”

Harry, who swam to raise money for the charity Together for Mental Wellbeing, says he may consider tackling the Channel for real one day.

Centre duty manager Corey Hill said: “Harry was very enthusiastic and determined to stay in the pool, he had little pool-side snacks and only got out for toilet breaks.”

As well as having his friends’ support, he had his family and visitors to the centre cheering him on and raising cash for the cause.

“He had his own lane but the pool was open to the public as normal throughout the day so he had lots of support – and he had to be really focused,” Corey added.

Harry’s girlfriend Chloe Piper kept count of each lap and swam the last 250 lengths with him, giving him an extra push to reach his goal.

Amy Edmunds, communications manager for Together, said: “We would like to congratulate Harry for completing this challenge – he has clearly worked really hard and should be proud of this achievement.

“The money he has raised for Together will help us to support more people with mental health problems to live independent, fulfilling lives.”