POLICE are bracing themselves for a spate of criminal damage and anti-social behaviour over the Hallowe'en period, the second busiest of the year.

Only the New Year period has more reports of crimes. Police are warning that vandalism by trick-or-treaters will be treated as a crime.

Chief Inspector Mick Pryce said: "If you don't want the trick to be on you this Hallowe'en, make sure that you act sensibly and think about whose door you knock on.

"Many of the incidents we are called to involve flour and eggs being thrown as part of trick-or-treating.

"These items can cause permanent damage to property and as such are reported as crimes.

"Community patrols will be increased and those people who choose to act anti-socially will be dealt with robustly.

"If anyone is concerned about trick-or-treating they should contact police while it is going on."

Shops across Hertfordshire have been given posters to display in their windows saying eggs and flour will not be sold to shoppers unless it is part of a larger grocery purchase.

Police say parents should keep an eye on their egg and flour supplies to stop them being misused.

Posters have also been designed for residents to put in their windows to fend off tricksters and warn them that police officers are on patrol.

The posters are available from the Harpenden community team on 01727 796143.

Officers says that to stay safe on Hallowe'en, youngsters should stick to the following guidelines: - Adults should always accompany children when trick or treating - Young people should never go trick or treating alone - Do not knock on the doors of strangers only go to people you know - Always keep to well-lit areas; - Wear bright clothing and remember the basics of road safety - Keep your "tricks" within the law anything that results in damage is an offence and will be dealt with as such; - Do not visit elderly people unless it has been agreed beforehand; - If someone calls at your door, be cautious. Use a door chain or door viewer to check the caller's identity. If you are unsure, do not open the door; - If you are happy for trick or treaters to call at your door, remember to stock up on treats.