A BRIT chemist who helped flood the UK with meow meow has warned of an even DEADLIER legal high about to hit us.
Worried Dave Llewellyn told The Sun that the new drug NRG-1 will be "Britain's worst nightmare" leading to mass brain damage and death.
NRG-1 ... 'juices the brain and causes cerebral burn out'
The horror drug COSTS just 25p a hit compared to £10 for a rock of crack cocaine, yet it is 13 times STRONGER than coke and even more ADDICTIVE than heroin.
But authorities are powerless to prevent it flooding our streets because it is completely LEGAL.
Dave, a drug manufacturer and legal stimulant seller based in Belgium, said yesterday: "It is the worst drug ever to hit the shores of Britain. It makes meow meow look like baby powder.
"It will wreck hundreds of lives and kill many times more than meow meow - and far more horrifically. It will make users want to tear out their own eyes.
"It makes people feel like God Himself - but really it is the Devil's Powder."
Scots-born Dave admits sending meow meow to Britain but has stopped after it was implicated in 26 deaths. He agreed to speak to The Sun amid moves to make the substance, officially known as mephedrone, illegal in Britain.
He turned whistleblower to us in a bid to prevent NRG-1 - which also has the street names Energy 1 or Rave - reaching the UK's markets too.
He said the new drug, otherwise known as naphyrone, would kill and mentally destroy so many people it would quickly "fill an Olympic stadium".
Speaking to us in the port city of Antwerp, he warned: "Naphyrone comes from Chinese factories and what it does to users is truly frightening.
"It will make them feel like God for about 12 hours. But when it wears off they will feel worse than they ever have in their lives. They won't sleep for three days.
"It juices the brain, causing cerebral burn-out of a degree not seen before. It causes paranoia and suicidal tendencies and permanently alters brain chemistry with horrifying consequences."
And he went on: "The worst thing is that it is completely legal. It is being marketed as a mephedrone replacement and will be bought by children.
"It can be made by anyone with a GCSE in chemistry for around 10p a gram. That would give one person around 80 hours of the ultimate legal high, then destroy them.
"Such a tiny amount is needed that it will turn up in playgrounds for 25p a hit. I think it will become Europe's crystal meth."
Dave said each hit of naphyrone was 13 times more potent than cocaine. And just a few granules of the off-white powder have the chemical effect of a "mega speedball" - like taking crystal meth, cocaine and ecstasy combined.
Dave added: "I won't sell meow meow again because of what has happened in Britain, with people selling the drug and then not telling them it can become lethal when mixed with alcohol.
"Marketing it as plant food is the most idiotic thing that could ever happened. That decision cost lives.
"But naphyrone is the one that sends shivers down my spine. I won't touch it and want to warn people how terrifying this drug is."
Dave, who left the UK to run Alchemy Labz selling "ethical" stimulants on the Continent, showed us dozens of websites already flogging naphyrone to Brits.
And drugs forums are crammed with questions from excited youngsters about the "brand new" meow meow - at the same time as seasoned users warned against it.
Warning ... the molecular make-up of ecstasy, mephedrone and NRG-1 are terrifyingly similar
One posted: "It is flying to Heaven - and waking up in Hell."
The chemical make-up of both mephedrone and naphyrone are only slightly different - and BOTH are terrifyingly similar to ecstasy.
Dave explained that mephedrone gives users a high by overdosing the body's pleasure receptors.
But naphyrone works by over-stimulating not only those receptors, but also ones which flood the body with adrenaline. The combination causes brain "fry-out".
Dave has written to Home Secretary Alan Johnson and the Drugs Advisory Council about his fears.
He insisted: "No drug is safe and I am definitely not advertising meow meow now. If I ever thought there was a one per cent chance someone would die from a drug I would not sell it at all.
"I understand the chemistry and I want to do the right thing. There needs to be serious action taken, driven by facts and not hysteria.
"There needs to be an open discussion and it needs to hear from law enforcement officers, politicians, youth workers, scientists - and also drug users."
UK drug websites were buzzing with talk about the new substance last night. One user who had tried it warned: "Can't sleep, very bad comedown. Sweating all night."