Methadone and buprenorphine have long been used by the NHS as a treatment programme to help people addicted to heroin.

A new measure could lead to heroin injecting facilities being piloted for drug users in Glasgow, where they would be given medical grade heroin under supervision.

NHS Greater Glasgow and Clyde has been working on the plans since June, with Glasgow City Alcohol and Drug Partnership recommending they are given the go-ahead.

It would not be the first facility of its kind in the world, with 90 centres already running across 61 cities. The earliest was launched in the mid-1980s.

Here we look at how similar facilities around the world have fared.

The Alpine country faced a widespread drug problem and decided to tackle it with the use of diamorphine distributed at official facilities rather than methadone prescriptions.

There are 22 centres around the country since the scheme began in 1986, including two inside prisons, with around 1500 being assisted yearly.

According to the Swiss Institute for Addiction Research, half of those who sign up remain on the programme for at least two and a half years while one in five remains on it for at least 15 years.

After the first centre opened in Switzerland, more were established across Europe. One of the first ventures outwith the continent came in 2001 in Australia with the Sydney Medically Supervised Injecting Centre.

The annual running costs of £1.87m a year are said to be equivalent to imprisoning 30 convicts, with the scheme receiving praise for the mental and physical health benefits stemming from work done in the drug consumption rooms.

As well as heroin, many who use the facility have been affected by cocaine or infected by Hepatitis C or HIV.

Two years later, the idea was trialled in Canada when an Insite centre opened in 2003.

Last year it was claimed nearly 1000 people visited the programme each day. It costs roughly the same as the Australian model.

Like many of similar facilities, Insite has come in for criticism and opposition, including from the country's then-prime minister Stephen Harper in 2011.

Drugs are not supplied at the clinic with medical staff instead supervising injections and providing mental health treatment. There have been no fatalities since it opened 13 years ago.

Earlier this month, the first French supervised space opened in northern Paris, linked to Lariboisiere Hospital.

It is the first of three rooms planned, with Strasbourg and Bordeaux also under consideration.

Around 200 people were expected to use the site each day. It is still too early to say how close this estimate is for the €1.2m facility, which has a dozen cubicles for users who do not have to provide their real name upon registration.

It has been labelled a "shooting gallery" by some critics, with local residents also unhappy about it opening close to a busy train station despite the fact a separate entrance is used from the main hospital.

In June it was reported Ireland would join the list of ten countries to provide a supervised centre in Dublin. It is believed the facility will be opening around this time next year.

Legislation came into effect in 2015 controlling drug possession and banning previously legal drugs in a bid to start tackling the problem while plans for a facility are still processed.

One media outlet spoke to the doctor who runs the Sydney MSIC, who was meeting campaigners backing the similar scheme in Ireland.