The gruelling swim will test the endurance of five ‘ordinary blokes’ from North Devon.

Cold water and strong tides are no match for a group of North Devon men taking on the swimming challenge of a lifetime.

The group of five already set a record time in 2009 swimming from Lundy Island to Woolacombe Beach in seven hours and three minutes.

But now Paul Irwin, 45; Bruce Hughes, 43; John Jameson, 34; Karl Whittaker, 42 and Jon Parker, 44 will be swimming more than 100 miles from Guernsey to South Devon.

Paul, a partnership development manager for pharmaceutical company Sanofi, said: “This is a big step up from our last challenge; it’s 81 miles as the crow flies, but with the tides it will probably end up being in excess of 100 miles.

“We’re doing it as a relay swim, which means we could all end up swimming the distance of the English Channel individually.”

Weather-depending, the group will set off from the Channel Island on August 24, and aim to arrive on the shores of Slapton Sands within 48 hours.

“We all love swimming and enjoy keeping fit, but at the end of the day we’re just a group of ordinary blokes,” said Bruce, a North Devon GP and medical director at the Children’s Hospice.

“It’s all about being a team and the trust we have, if we all work together then we can achieve this.”

The challenge is the pinnacle of more than a year of gruelling training sessions slotted in around the team members’ busy lifestyles.

John Jameson, who also works for Sanofi, said: “This is a lot more extreme than the Lundy swim; I don’t think it’s something one person could do on their own.

“We’ve been very lucky to have a lot of support and sponsorship so far as well as a great team behind us.”

During the swim, the swimmers will be accompanied by medics and support staff on kayaks, and are hoping to raise £10,000 for the Teenage Cancer Trust.

The Great Big Monster Sea Swim is the headline event of the Sanofi 1,000 Mile Challenge, which aims to raise £100,000 for the charity through employees collectively achieving 1,000 miles of activity.

To sponsor the swimmers in their challenge, visit www.justgiving.com/gbmss