Why do thousands run the London Marathon in costume?

Alex Morris said running the London Marathon while dressed as a polar bear was the hardest experience of his life [Sportograf] Every year, tens of thousands of runners flock to the start of the London Marathon, eager to prove they can go the distance. There will also be plenty from across the country at Sunday's London Landmarks Half Marathon. While many athletes take part in standard running gear, there are those who choose to tackle the 26.

2-mile (42. 2km) course in weird and wacky fancy dress. While it adds spectacle, humour and joy, running with the extra layers or awkward clothing items presents its own challenges "It was the single hardest experience of my entire life," said Alex Morris, almost a year after he completed the race wearing a polar bear onesie.

He had not run a marathon since his early 20s but decided to take part in aid of mental health charity Mind. Morris did more than 200 miles of training and became known as "the polar bear guy" in his hometown. But the 36-year-old, from Shrewsbury, also found out how restrictive his outfit was as he was forced to adapt his running style due to how difficult it was to move his legs freely.

Alex Morris said it was a "rewarding day" [Sportograf] His biggest adversary on the day was the heat, made worse by the onesie, which led to him losing about 2kg of weight. His marathon became a "constant battle" of putting one foot in front of the other and despite a few "frank conversations" with ambulance staff, he managed to complete the course in just over five hours. "It was just so horrific," Morris said, "but I managed mile after mile, half mile after half mile, to eventually get to the end.