Shark filmed swimming 10 miles inland on the River Stour, Essex

Jody Gibbons, 27, recorded the video of Sunday afternoon, while walking beside the Cattawade Sluice. Experts think the beast, estimated to measure 4ft to 5ft, could be a shallow water smoothound shark. Mr Gibbons, who was with his father at the time, said: "It was unbelievable to actually see something like that down this way. "I saw this fin popping out of the water. As I got closer I saw it was a shark." University of Southampton shark expert, Dr Ken Collins thinks the shark may be a smoothhound, which commonly swim close inshore.