Four out of five shops selling butane gas in Worthing illegally serve it to children.

Trading standards officers used a 14-year-old girl in random checks at the shops. The lighter refills should only be sold to over-18s.

Officials said they were concerned shop staff seemed to be unaware of the law regarding the product.

Lionel Barnard, West Sussex County Council Cabinet member designate for public safety, said: "Generally, retailers in West Sussex seem aware of the age restrictions of tobacco and alcohol.

"However, we are very concerned that this potentially fatal product is so readily available to young people.

"These refill canisters have been responsible for far more deaths than ecstasy, yet receive far less publicity.

"There appears to be a lot of work still to do to make retailers aware of their responsibilities in this area.

"Proof-of-age cards, such as CitizenCard, are now freely available to youngsters throughout West Sussex and there is no excuse for any retailer not to demand to see these before selling such dangerous products."

Patrick Bligh-Cheesman, head of trading standards, said tough action would be taken against any business that persisted in selling these products to young people.

He said: "On this occasion only warnings are being issued to those involved.

"But in future no second chance will be given and those caught will find themselves in court.

"Young people who abuse this substance frequently get no second chance and trading standards will not be giving the sellers a second chance either.

"A recent case taken by Staffordshire Trading Standards in Uttoxeter, where a 15-year-old volunteer was able to purchase a butane gas lighter refill, resulted in the company being taken to court and having to pay almost £10,000 in fines and costs.

"Regrettably, heavy fines are sometimes the only way retailers take notice."