Little Britain comedian David Walliams has completed his latest challenge, an eight-day swim of the river Thames from Gloucestershire to London and raised a staggering £1.2 million for Sport Relief.

Walliams’ 140 miles challenge started at the river’s source near Lechlade finished at Big Ben and he was accompanied throughout by HK author Professor Greg Whyte, who teaches Applied Sport and Exercise Science Liverpool at John Moores University.

Greg Whyte, author of HK title Practical ECG for Exercise Science and Sports Medicine, has been coaching Walliams throughout the year.

Greg has previously trained Walliams for his Sport Relief swims across the English Channel in 2006 and 2010 and was also responsible for coaching actor and comedian Eddie Izzard on his incredible achievement of running 43 full marathons in 51 days in 2009.