A blanket ban on so-called legal highs has come into force in the UK.
Laws criminalising the production, distribution, sale and supply of what are otherwise known as new psychoactive substances began at midnight.
The chemicals, sold under names such as spice and black mamba, are designed to give users the same effect as drugs like cannabis and cocaine.
Last year legal highs were linked to more than 100 deaths in the UK and a rise in violent assaults in prison.
Offenders who break the new laws will face up to seven years in prison under the Psychoactive Substances Act.
Police will also be able to shut down “headshops” – stores which sells drug paraphernalia – and online dealers in the UK.
However, there have been warnings the ban could drive the sale of the drug to the so-called “dark web” – a largely untraceable area of the internet that does not show up on traditional search engines.
Simon Blackburn, of the Local Government Association, said legal highs were a “scourge on society and shatter lives”.
He added the new blanket ban “should help to reduce anti-social behaviour” linked to their use.
“Councils have made every effort to crack down on these substances and the unscrupulous traders selling them, which has seen so-called ‘head shops’ closed down, intoxicating substances seized, on-the-spot fines issued and successful prosecutions.
“However, this work relied on laws designed for very different purposes, making it much harder for councils and the police to tackle the problem.”