Nineteen-year-old Callum, who lives in Avon Avenue, has swam the half-marathon on behalf of the Teenage Cancer Trust.
That’s 13.1 miles in total; or a mind-boggling 21,082 metres if you prefer!
To put that into some context, American Phelps – the most successful Olympian the world has ever seen – swam a total of 8500 metres in the pools of Athens, Beijing and London on his way to 18 golds, two silvers and two bronze medals at the past three Olympic Games. So it was a massive challenge that Callum set himself and his training schedule reflects that.
He has swum over 170 lengths of the 20 metre pool at Carluke Leisure Centre and the 25 metre pool at Lanark Lifestyles Centre.
For more on this story pick up a copy of the Carluke Gazette, which is in the shops now.