Latest Videos From Horse & Hound Watch full video here:River keeper Mark Cameron, who works for the landowner, the Ernest Cook Trust, came up with the idea of asking for Harry to help. Mark said: “Harry was in and off up the river like he had been doing it for ever. The rush of excitement was incredible, to be walking through the river ahead of three quarters of a ton of working horse was amazing. The Ernest Cook Trust, which owns 10 estates from Dorset to Cumbria, is a charity that uses the income generated by its land to support education of children and young people in the countryside. To stay up to date with the latest equestrian news, subscribe to the Horse & Hound website