POLICE and child psychology experts have called for an end to the 'Killer Clown' craze sweeping the country as officers investigate yet another incident in which children were left terrified as they made their way to school.

On Friday morning, four children were left distressed after a man dressed as a clown and carrying a knife pounced from bushes and chased them towards school.

Police say the children, aged 11 and 12-year-old, arrived at Hermitage Academy in Chester-le-Street “upset and distressed” after the incident, the latest in a string of copycat pranks originating in the USA and inspired by the best-selling novelist Stephen King’s Pennywise character.

King sent a Tweet to his 2.4 million followers saying: “Guys, time to cool the clown hysteria – most of ‘em are good, cheer up the kiddies, make people laugh”.

Now police are calling for an end to the craze, because of the potential harm to child victims.

Sergeant Mel Sutherland, of Chester-le-Street Police, said: "I would like to appeal directly to the people who are dressing up and carrying out these stupid acts to think seriously about what they are doing, the distress they are causing to young children is unnecessary and it needs to stop."

The children were walking towards school at 8.40am this morning when a man dressed as a clown and carrying a knife jumped out of bushes and chased them.

He was wearing grey tracksuit bottoms, red shoes, a multi-coloured top and was described as wearing a mask as well as having his face painted.

Sgt Sutherland added: "The children arrived at school understandably upset and distressed by this incident and we are currently trying to locate this man.

“My officers will be on patrol outside the school at home time this afternoon to offer reassurance to children and parents.

"We believe this to be part of a much larger prank which is currently sweeping across the USA and parts of the UK.

“It is very alarming he was carrying a knife however we do not think he intended to harm the children and as far as we are aware, this is part of the prank.

"There are currently several social media accounts dedicated to this 'Killer Clown' craze and we are also looking into those and who is using them”.

Hermitage Academy principal Felicity Smith said: “Following the incident that happened in the community this morning we are supporting the police with their enquiries.

“All parents and local schools have been informed to raise awareness and promote the safety of all children in Chester le Street”.

Last week, a 13-year-old boy was arrested after six incidents in one day on Tyneside, while earlier this week police were called to Newton Aycliffe after reports of a man hiding in bushes dressed as a clown.

Just after 6pm on Thursday, police were called to Brotton, near Middlesbrough after a man dressed as a clown and possibly carrying a knife scared a girl in the village park.

A spokeswoman for Cleveland Police said: “Police were contacted after a young girl had reportedly seen a person wearing a clown mask and possibly in possession of a small knife standing in bushes at Byron Court, Brotton, in a park known locally as Mushroom Park”.

She added: “The girl was not followed or physically harmed in any way and officers are continuing to make enquiries”.

In the last few days, other incidents have been reported in Suffolk, Leeds, Essex, Cheshire, North Wales, Dundee, Norwich, London, Manchester and Sheffield.

Newcastle-based child psychiatrist Dr Stephen Westgarth said that, while a majority of children would eventually laugh off such an incident, a sizeable minority could suffer years of lasting psychological damage.

He said: “A knife is a deadly weapon and that really steps it up: it says to them this is a weird, sick and dangerous person.

“There will be some kids who would just have a bit of a laugh, especially if they are a secure and confident child.

“For the majority, they would be anxious for a few days and, although a few days of fear for a child is bad enough, there would be no lasting effects.

“But there would be a sizeable minority, perhaps between 10 and 25 per cent, who could have really significant anxiety.

“There is a risk they would be fearful of going out, inappropriately fearful of strangers and it is not beyond the bounds of possibility that a child could be at risk of post-traumatic stress disorder if they perceived themselves to be in a potentially deadly situation.”