A pilot scheme carried out in Fife to raise awareness of the problem was deemed successful enough to make the use of the tactic — which often attracts controversy over issues of entrapment — legal across the country.

The new measure will see councils armed with the power to use young people under-18 as decoys to check that retailers are carrying out the necessary age checks.

Dundee City Council welcomed the step and the Lord Advocate’s decision to grant test purchasing under a revision of the law.

“This is something that would be used where appropriate in a targeted way,” said a spokesperson.

Methil man John O’Brien, whose son Lee died three years ago after sniffing the solvent, was at the launch in Edinburgh today and hailed the “brave” decision taken by the Scottish Executive.

“This is a very positive move by the Scottish Executive — a step that will give all local authorities in Scotland the opportunity to test purchase shopkeepers to catch them out and make sure they are being responsible,” he said.

“Some of the retailers don’t know these solvents are so dangerous and this will hopefully make them more aware.”

Mr O’Brien has campaigned hard for a change in the law and set up the Lee O’Brien Solvent Trust (LOST) following his son’s death.

“My own son died as a result of solvent abuse.

“If a shopkeeper had taken a moment to ask my son how old he was he might be alive today.

“I am so happy that my son’s tragedy has resulted in something positive.”

Re-Solv, a national charity dedicated to the prevention of solvent and substance abuse, said it was about time Scottish councils were able to use the same measures as their counterparts in England, Wales and Northern Ireland.

Speaking at today’s announcement, Director Warren Hawksley said, “We welcome this move by the Scottish Executive because the use of test purchasing is already used in the rest of the United Kingdom.

“It is something we have been fighting hard for in Scotland.

“It is a retailers’ campaign and sends out the message that solvent abuse can kill and it is illegal to sell these products to anyone under-18.”

Deputy Justice Minister Hugh Henry said, “It is vital to raise public awareness of the dangers of abusing products such as cigarette lighter refills, aerosol sprays and glue.

“We must persuade youngsters who may not fully appreciate the risks involved that there is no safe way to sniff or inhale volatile substances.

“That is why this awareness campaign is so important.

“Aiming the campaign at shop owners should not be seen as implicit criticism of the retail trade — the vast majority of shop staff act responsibly and within the law when it comes to selling age-restricted goods.”

Sniffing lighter fluid gives a temporary high but can have serious consequences, sometimes resulting in death.

Fife Council piloted a scheme last year where Fife Council were actually testing the shopkeeper on the sale of butane gas (cigarette lighter fuel).

As a result, 50% of shopkeepers failed the test.

They actually sold to under-age youngsters, proving the point that test purchasing was needed to combat the sale of cigarette lighter fuel.

Today the deputy justice minister launched a national test purchasing scheme which allows all councils in Scotland to test purchase all shops in Scotland to make sure that they are trading legally and not selling butane gas to youngsters under-age.

It shows they are committed to promoting health and safety in all communities.