Police have issued a warning after 12 canisters of concentrated nitrous oxide, commonly known as laughing gas, were stolen from a Suffolk hospital today.

The theft took place at around 4.40am in the grounds of Ipswich Hospital in Heath Road.

The suspects are believed to be four men who left the premises in a dark coloured hatchback car.

A spokeswoman for Suffolk Constabulary said: “The canisters contain the anaesthetic gas nitrous oxide which could be harmful and potentially lethal if inhaled/ingested by members of the public.”

The canisters are approximately 4ft high, blue with a white stripe around the top.

Nitrous oxide is often used as a party drug and was once dubbed “hippy crack” by a national newspaper.

Witnesses or anybody who has any information regarding the whereabouts of the canisters are asked to call police 101 quoting reference 62 of today.

Alternatively contact Crimestoppers anonymously on 0800 555 111 or at www.crimestoppers-uk.org.