A 13-year-old from Staines-upon-Thames who has been shielding for 10 months to protect his father while he receives treatment for a rare brain tumour, completed the 'London Marathon' - in his garden.
William Priddy started the 26.2-mile run at 9.30am on Sunday - just as the starting gun fired in Blackheath - and finished 10-hours later.
Mirroring the Virgin Money London Marathon around the family's garden, the course even took in several of London landmarks that runners see along the route, including the Cutty Sark, Tower Bridge and the Thames Barrier.
William took up running during the first lockdown last spring after a teacher encouraged him "to do something positive in hard times" after the family were forced to shield.
Earlier this year, William set himself the challenge of running one mile every day for one year, a challenge he is due to complete on 4 January 2022.
William doesn't give in, even when he gets caught in a downpour
William hopes his latest marathon effort will raise even more for Brain Tumour Research, a charity for which he has already raised £10,000 for.
To make the experience "more real" William enlisted the help of his mother, Joanne, and her creative talents to help make props of some of London's most famous sights.
His mum Joanne, 40, said: "Wills asked if I could make all of the landmarks the runners see so that it feels like he's there. It'll make it feel more real to him and obviously to end it I've had to order a balloon arch because he has to feel like he's running under it for his last lap."
William, who 'is Harlequins crazy' and gets his stamina from playing for Chobham Rugby Club, completed 1,992 laps of his garden during the marathon, with each mile consisting of 76 laps. Cheered on by Joanne, her dad, Greg, 45, and sister Amelia, 15.
Crossing the finishing line
The family have now been shielding for 41 weeks and are currently awaiting the results of Greg's latest scans to see whether or not he is in remission after having treatment for a rare cancerous brain tumour.
Charlie Allsebrook, community development manager for Brain Tumour Research, said: "William has such a bubbly personality that it's not surprising he's managed to turn something so scary into something so positive - it's truly admirable."
Brain Tumour Research funds sustainable research at dedicated centres in the UK. It also campaigns for the Government and the larger cancer charities to invest more in research into brain tumours in order to speed up new treatments for patients and, ultimately, to find a cure. The charity is calling for a national annual spend of £35 million in order to improve survival rates and patient outcomes in line with other cancers such as breast cancer and leukaemia and is also campaigning for greater repurposing of drugs.
William wants to encourage everyone to donate at least £1 to his cause. To do so, visit braintumourresearch.org citing WP when making a donation.