Hundreds of empty silver cannisters have been found on street pavements and in parks.

The cannisters were collected in Chorleywood - and now Three Rivers District Council is urging parents to check if their children are carrying canisters of Nitrous Oxide.

Silver canisters of Nitrous Oxide, commonly known as ‘laughing gas’  are dispensed into balloons for inhalation.

Legislation passed in 2016 made it illegal to sell the gas for psychoactive purposes.

The council has said it is committed to reducing and preventing anti-social behaviour across the district.

Cllr Roger Seabourne, Lead Member of Community Safety and Partnerships, said: “People need to be aware of the risks involved with the use of Nitrous Oxide which are certainly no laughing matter. There are serious physical and psychological effects as there are with the abuse of any substance.

“I would ask parents to watch out for their children buying these canisters, often through online sites, and look out for the signs of use. More information about drugs, and the symptoms and side effects of their use can be found online at”.