Swimmers in France, book now

Places fill up quickly for the “Everest of swimming” challenge, which is open every year from the first week of June to the first week of October.

It is advisable to book more than a year in advance for training and certification purposes.

Those who take part must have completed a minimum six-hour “cold-water” swim – or two-hour swim for those taking part in a relay.

A medical certificate is also required.

Everyone who takes up the challenge to swim the 33km of the world’s busiest shipping channel must be accompanied by a pilot approved by one of two organisations – the Channel Swimming Association or the Channel Swimming & Piloting Federation.

Tides mean most will end up swimming closer to 50km, taking 10 to 12 hours.

Pilots, who are all British as all challenges set off from England, have to be paid in advance – at a cost of £2,400.