The NSPCC has warned that paedophiles might take advantage of the 'clown craze' to dress up on Halloween and try and molest children.
The charity urged parents to be 'extra vigilant' when out trick-or-treating with their children, as clown-related incidents in the UK reach 'epidemic' proportions.
Childline reported receiving 462 calls from terrified children in a three-week period.
139 children under the age of 11 required counselling, with the telephone helpline service responding to 84-clown related calls in just one day. Three quarters of the calls were from young girls, Mail Online reports.
The 'killer clown craze" which began in the US, is now sweeping across the UK, with hundreds of reported sightings of clowns wielding knives or baseball bats frightening children.
On 15 October, a machete-wielding man in a clown outfit threatened two young girls in Bury St Edmunds. One suspect wearing a clown mask and carrying a fake gun was arrested by police about five miles from Heathrow Airport. Children have also been targeted online, with a teenage girl receiving threats on Instagram.
British police forces have issued guidance for anyone worried about a possible threat and issued a warning to those dressing up as clowns ahead of Halloween that they could face action.
A police spokesman told the BBC: "We are continuing to receive reports of the clown craze, which is causing distress and fear to people in our community. We appreciate that the majority of the public understand the impact and harm that this is causing, particularly to children.
"We are hoping that this craze will pass this week and we would urge the small minority of people still taking part to stop. Dressing up as a clown and deliberately trying to scare and intimidate others is causing a lot of distress to people and we will not tolerate it.
"This prank could lead to arrests for public order offences, possession of offensive weapons or even assault."