Suppliers of so-called legal highs that mimic the effects of Class A drugs will now face up to seven years in prison after the substance was outlawed at midnight.

Eastern Daily Press: Some of the legal highs seized by Norfolk County Council Trading Standards from shops in Norwich before they were banned in May this year. Picture: ANTONY KELLYSome of the legal highs seized by Norfolk County Council Trading Standards from shops in Norwich before they were banned in May this year. Picture: ANTONY KELLY (Image: Archant Norfolk 2015)

The blanket ban on previously legal highs now criminalises the production, distribution, sale and supply of the new psychoactive substances - or designer drugs which saw an explosion in popularity on the drug scene in around 2008 and 2009.

Two people died of legal highs in Norwich last year and Norfolk Police have welcomed the ban.

Ch Insp David Buckley said: 'The greatest concern is that anyone taking them does not know what they contain. Police will now have the powers to take action against anyone involved in illegally supplying them or importing them.

'We are encouraging the public to let police forces know if they believe shops or establishments continue to supply psychoactive substances.'

The rise in the use of legal highs was a challenge for existing drugs laws, with new substances being developed at such speed that by the time one was banned, another with a slight change in chemical structure could take its place on the market.

A number of deaths have been linked to taking them.

In Rochdale alone, nine people in the past week have fallen ill after taking the substance - including one 24-year-old man who remains in a critical condition in intensive care having suffered a cardiac arrest after taking a substance called Clockwork Orange.

The substances mimic the effects of 'traditional' illegal drugs like cocaine, cannabis and ecstasy.

Greater Manchester Police (GMP) said it had been a 'worrying development over a short space of time' and welcomed the new legislation which had been pushed back a month.

But questions have been raised over how far it will deter users with warnings that it could drive dealers on to the 'dark web'.

Police will have new powers to shut down 'headshops' and UK-based online dealers, helping to protect potential users from harm and communities from anti-social behaviour.

A number of legitimate substances, such as food, alcohol, tobacco, nicotine, caffeine and medical products are excluded from the legislation.