The Channel attempt will take between 10 to 15 hours

Olly White, who teaches at Kentisbeare Primary School, will use the money he raises from his 22-mile (35.4km) dip to boost the school's swimming programme.

The 27-year-old has piled on about two stones (12.7kg) to prepare for his marathon in August.

Mr White said swimming not only helped children get fit, but had confidence and safety benefits.

The national curriculum states that children should be able to swim 25m by the age of 11 - a distance exceeded by many of Kentisbeare's pupils. The money raised will help pay for pool hire, swimming instruction and transport.

We've been doing some geography, looking at sea charts and doing some work on sea depths and the oceans Olly White

Mr White told BBC News his Channel swim venture had led to other teaching opportunities for the children.

"At first some of them didn't comprehend exactly what the English Channel was", he said.

"So we've been doing some geography, looking at sea charts and doing some work on sea depths and the oceans."

Mr White, a member of the British Long Distance Swimming Association, completed a 21-mile swim of Lake Windermere last year. He is currently training for up to eight hours a day off the south Devon coast, swimming about 17 miles.

He will begin his attempt from Shakespeare beach near Dover and, depending on weather and tides, should arrive at Cap Griz Nez in France about 10 to 15 hours later.