The Essex Lion: a lioness in the stubble and a police hunt at St Osyth (2012)

August Bank Holiday weekend, 2012. St Osyth is a village near Clacton-on-Sea, in the Tendring district of Essex. The holidaymakers at the centre of this story were staying in neighbouring caravans at the Earl's Hall Farm Caravan Club site.

Sunday 26 August. Just before 7pm. By one account, Denise Martin, 52, of Canvey Island, went out to look at smoke rising from a field off Earls Hall Drive. Across it she saw a shape, sitting in the stubble. "It was bigger than a German Shepherd, and it was female," she said. "It was too far away for us to be scared. It was looking at us, its ears were twitching."

Her husband, Bob Martin, 51, put it "several hundred yards" away. "It was cleaning itself as if it had just eaten," he said. In the next caravan, Denise's brother Dave Wright, 57, took photographs on a digital camera from about 200 yards. His wife, Sue Wright, 58, was certain. "There is no doubt in my mind that we were looking at a lion, a female lion because it did not have a mane."

Stephen Atkin, 52, watched it "for about 20 to 30 minutes cleaning itself and rolling about in the field". He said it was the length of two sheep put together. Gill Atkin, 51, was less sure. "I did not think it was a lion as its ears were too pointed but it was really big."

Denise Martin reckoned it stayed about an hour. Then it "slouched down and crawled off into the bushes." At 10pm, local resident Che Kevlin heard "a loud roar". "It sounded like a lion."

Essex Police took no chances, and armed officers went in. Two police helicopters with thermal-imaging equipment searched from above. Colchester Zoo staff came with tranquilliser guns. Residents were told to stay indoors and ring 999 if they saw the animal. Zoo experts shown one of Dave Wright's photographs at first believed the reports to be genuine.

Colchester Zoo said all its animals were accounted for. A circus that had visited Clacton had no lions at all. Essex Police later told a BBC Freedom of Information request that 31 officers were deployed at various times during the incident. The total cost, it said, was not known.

At 2pm on Monday 27 August, the search was called off. "We believe what was seen on Sunday evening was either a large domestic cat or a wildcat," police said. "Extensive searches have been carried out, areas examined and witnesses spoken to; yet nothing has been found to suggest that a lion was in the area." Roger Lord, the site's co-owner, was sceptical too, and thought "it might just well be a large domestic cat". The people police interviewed stayed convinced they had seen a lion.

Soon the suspects had names. Ginny Murphie, 50, of St Osyth, said it was probably her 3-year-old ginger Maine Coon, Teddy Bear, who regularly hunts in the fields near the village. The Daily Mirror named Tom, a 12-year-old ginger tomcat living nearby. Colchester Zoo's Sarah Forsyth called the photographs "very poor quality" and thought a dog more likely. Police never confirmed either cat.

Online, the Essex Lion roared on. A parody Twitter account, @EssexLion, opened with "ROAR BRUV!" and gathered tens of thousands of followers in under two days. Police warned that doctored photographs were circulating on social networking sites. No animal was ever found, and fourteen years on a local retrospective still called the mystery unsolved. The case belongs to a wider tradition, the British big cats, the alien big cat sightings that recur across the country.