Last summer its pastures and parkland were the setting for a major police operation as dozens of officers and helicopters searched in vain for what was quickly dubbed the "Essex lion".

Almost exactly a year on however, the same English county finally appears to have offered some wildlife not usually associated with its countryside − in the form of a shark.

The four-foot fish was captured on film by a walker strolling along the banks of the river Stour after he spotted a fin sticking out of the water.

"As we walked past we saw a big fin sticking up out of the water and thought 'that must be a big fish'," said Gary Gibbons, a marketing executive who was walking with his father.

"That thought quickly became 'that's a massive fish' and then I realised it was a shark. I really could not believe what I was seeing.

"We have walked along there so many times before but never had I seen anything like that before."

Gibbons from Lawford, Essex, spent more than an hour watching the shark and filming footage in which it can clearly be seen swimming past in shallow water. He gave a "conservative" estimate that the shark was at least 4ft long but thinks it may have been 5ft long.

"It was an amazing sight and I knew I had to film it, otherwise my friends would not have believed a word I was saying," he added.

"The water was quite shallow where we saw it and its fin was sticking out of the water − it was like a scene from Jaws.

"You do get people fishing here and there is a beach further up the river but it's surprising to find a shark."

David Warner, commodore from the nearby Stour Sailing Club, said: "We have had sharks in the lowest point of the river before but not up where it was seen."

Britain's coastal waters are home to more than 30 species of shark, according to the Shark Trust.The International Shark Attack File (ISAF), a compilation of shark attacks administered by the the American Elasmobranch Society and the Florida Museum of Natural History, records only two unprovoked shark attacks in England since 1847, neither of which proved fatal.