LONDON (Reuters) - They have become a common sight in London's gutters after a hard night of partying: small, silver cylinders that contained nitrous oxide, or laughing gas, Britain's most popular "legal high".
But their days may be numbered after Lambeth council in south London became the first in Britain to ban the use of nitrous oxide.
Clubbers buy the metal bulbs for a few pounds and inhale the gas from balloons to induce a brief period of euphoria. The drug, sometimes called "hippy crack", has been linked to several deaths.
The popularity of laughing gas is growing, according to a government survey, in which 7.6 percent of 16- to 24-year-olds said they had taken it between 2013 and 2014, behind only cannabis.
The organisers of Europe's biggest green-field music festival, Glastonbury, banned it from some areas this year after 2 tonnes of used cylinders were left there last year.
But the recreational use of laughing gas - long administered as a pain-reliever in dentistry and childbirth and to initiate general anaesthesia - is nothing new.
The early 19th-century chemist Humphrey Davy first noticed its mind altering effect, and laughing gas parties took off soon after in both Britain and the United States as members of the upper class enjoyed the pleasurable 'hit' it offered with none of the nasty after-effects associated with alcohol.
Yet modern-day campaigners have blamed the drug for several deaths from asphyxiation as it displaces oxygen in the lungs.
An 18-year-old British boy died from nitrous oxide inhalation at a party in July and five people died in 2010, the government statistics office said. It also said 15 people die from the drug each year in the United States.
Lambeth council's new rules provide for a maximum fine of 1,000 pounds ($1,560) for using or supplying the gas after a month-long consultation with residents showed 63 percent favoured a ban, the council said.
The ruling Conservative party pledged in its manifesto for May's election to ban all "legal highs", including laughing gas.