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Almost 500 people have been arrested since a ban on so-called legal highs came into force six months ago, the Home Office has said.

Four people have been jailed and the government said more were progressing through the courts.

Psychoactive substances, which produce highs similar to cocaine, cannabis and ecstasy, were banned at the end of May.

A total of 332 shops have stopped selling legal highs and 31 selling drugs paraphernalia have closed down.

Of the 492 people arrested in the UK since the legislation took effect, it is not known how many have been charged with an offence.

'Dangerous drugs'

Home Office minister Sarah Newton said: "We banned new psychoactive substances because they are not safe, they can devastate lives and we will not tolerate them in this country.

"At the same time as supporting law enforcement in tackling the supply of illegal drugs we are also taking action to prevent the harms caused by their use, from educating young people about the risks to helping dependent individuals through treatment."

Commander Simon Bray, of the National Police Chiefs' Council, said the Psychoactive Substances Act had "fundamentally changed the way the police tackle the supply and distribution of these dangerous drugs".

The Home Office said new psychoactive substances were involved in 204 deaths in the UK in 2015, an increase from 163 the previous year.