27 August 2012 Last updated at 02:48 ET
Firearms officers and police helicopters have joined the hunt for the lion
Police in Essex are investigating reports that a lion has been spotted in a field near St Osyth.
Police - who initially told residents to stay indoors after the sighting in fields off Earls Hall Drive - are looking for signs such as pawprints.
Essex police are working with experts from Colchester Zoo who believe the reports to be genuine after being shown a photograph by a member of the public.
Local resident Che Kevlin told the BBC he heard a "loud roar" at 22:00 BST.
Armed police have been drafted into the area and two police helicopters are searching the area where it was spotted.
Asked whether the animal would be shot if it was found, spokeswoman Donna Veasey told the BBC officers had to consider the safety of the public at all times.
Essex police say about 25 officers are on the scene, including around a dozen specialist firearms officers, and experts from Colchester zoo are also on hand.
A force spokesman said officers would be returning to areas where the animal had been spotted during daylight hours to look for signs it had been there.
Police said all the animals at Colchester Zoo had been accounted for.
The spokesman said a circus had been in the area, at Clacton Airfield, recently but added: "Officers have spoken to the circus and confirmed that they do not have an animal missing, nor do they have any lions."
Caravan parksMr Kevlin said that shortly after hearing the roaring sound he got a text from a relative telling him a lion was on the loose in St Osyth.
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He said: "It was worrying as we had just been for a walk with the dog. We saw the police helicopter but thought it was just searching for a person.
"It sounded like the roar of a lion. We have field and wood just behind our fence, so you never know," he added.
There are several holiday caravan parks in and around St Osyth and Sean Williams, who is in a caravan, said he was worried about going out.
'Worried'Mr Williams, who said he heard about the lion on Twitter, said: "The children are with me and we are quite worried. We were out in fields in St Osyth but we're back in the caravan now.
"We've only seen one police car bombing it down the road. We had a fishing trip planned for tomorrow but we're now debating whether to carry on."
Dave Sparks, who runs the Red Lion pub in St Osyth, said it had been a "surreal" night and told ITV News: "You don't really expect to be told there's a lion wandering around the area.
"No one really felt there was any immediate danger in the village - a couple of families with young children were a bit worried but after a while they were okay."
Police are asking anyone who sees the animal to call 999.
The news of a potential lion on the loose has captured the public imagination and three Twitter accounts - @EssexLion, @TheEssexLion and @Essex_Lion - were quickly set up.
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Police in Essex are investigating reports that a lion has been spotted in a field near St Osyth.
Police - who initially told residents to stay indoors after the sighting in fields off Earls Hall Drive - are looking for signs such as pawprints.
Essex police are working with experts from Colchester Zoo who believe the reports to be genuine after being shown a photograph by a member of the public.
Local resident Che Kevlin told the BBC he heard a "loud roar" at 22:00 BST.
Armed police have been drafted into the area and two police helicopters are searching the area where it was spotted.
Asked whether the animal would be shot if it was found, spokeswoman Donna Veasey told the BBC officers had to consider the safety of the public at all times.
Essex police say about 25 officers are on the scene, including around a dozen specialist firearms officers, and experts from Colchester zoo are also on hand.
A force spokesman said officers would be returning to areas where the animal had been spotted during daylight hours to look for signs it had been there.
Police said all the animals at Colchester Zoo had been accounted for.
The spokesman said a circus had been in the area, at Clacton Airfield, recently but added: "Officers have spoken to the circus and confirmed that they do not have an animal missing, nor do they have any lions."
Caravan parksMr Kevlin said that shortly after hearing the roaring sound he got a text from a relative telling him a lion was on the loose in St Osyth.
He said: "It was worrying as we had just been for a walk with the dog. We saw the police helicopter but thought it was just searching for a person.
"It sounded like the roar of a lion. We have field and wood just behind our fence, so you never know," he added.
There are several holiday caravan parks in and around St Osyth and Sean Williams, who is in a caravan, said he was worried about going out.
'Worried'Mr Williams, who said he heard about the lion on Twitter, said: "The children are with me and we are quite worried. We were out in fields in St Osyth but we're back in the caravan now.
"We've only seen one police car bombing it down the road. We had a fishing trip planned for tomorrow but we're now debating whether to carry on."
Dave Sparks, who runs the Red Lion pub in St Osyth, said it had been a "surreal" night and told ITV News: "You don't really expect to be told there's a lion wandering around the area.
"No one really felt there was any immediate danger in the village - a couple of families with young children were a bit worried but after a while they were okay."
Police are asking anyone who sees the animal to call 999.
The news of a potential lion on the loose has captured the public imagination and three Twitter accounts - @EssexLion, @TheEssexLion and @Essex_Lion - were quickly set up.
Send your pictures and videos to [email protected] or text them to 61124 (UK) or +44 7624 800 100 (International). If you have a large file you can upload here.
Read the terms and conditions