Adam Walker is the first Briton to complete the Ocean's 7 challenge, a tough series of long-distance, open-water swims, which only five people have ever done.

It involves swimming the North Channel, the Cook Strait, the Molokai Channel, the English Channel, the Catalina Channel, the Tsugaru Strait and the Strait of Gibraltar.

Adam Walker started the challenge in 2008 and it has seen him contend with sharks and jellyfish stings and even swim with dolphins.

He told BBC Breakfast he started after watching a film about a man swimming the English Channel and thinking "I could do that".