Dance drug mephedrone will be banned within weeks, Home Secretary Alan Johnson said.
The legal high, which has been linked to up to 25 deaths in England and Scotland, will be banned and made a Class B drug, he said.
A ban on importing the drug will come into force immediately.
The announcement came after Mr Johnson was given a report backing a ban on mephedrone - also known as M-Cat or Plant Food - from Professor Les Iversen, chairman of the Advisory Council on the Misuse of Drugs.
Speaking at the Home Office after talks with Prof Iversen, Mr Johnson said he had accepted the council's advice.
The ban will cover not just mephedrone but all similar substances in a group called cathinones, he said.
It is likely to come into force by the end of April, he said.
"As a result of the council's swift advice, I am introducing legislation to ban not just mephedrone and other cathinones but also to enshrine in law a generic definition so that, as with synthetic cannabinoids, we can be in the forefront of dealing with this whole family of drugs," he said.
"This will stop unscrupulous manufacturers and others peddling different but similarly harmful drugs.
"My department will lay the necessary Order in Parliament tomorrow.
"I am seeking cross-party support to swiftly ban these dangerous drugs from our streets.
"Parliament permitting, I hope to do this in a matter of weeks. In the meantime, I have today banned the importation of mephedrone, other cathinones, and all products containing these drugs with immediate effect.
"The Government is determined to crack down on these so-called legal highs and we must all play a part in ensuring children and young people know about their dangers."
Drugs advisor
A leading drugs support advisor in Edinburgh had warned against such a move.
John Arthur, of Crew 2000, believes banning the legal high would only drive it underground and not stop people taking it.
His support centre has taken calls from thousands of users and other people concerned about mephedrone and its side effects.
He said: "It has had a very quick take up. We've never seen a drug like it. In the past year it has become one of the most popular drugs in Britain and right across Europe."
Mr Arthur does not believe young people were taking it because it was legal.
He said: "They know that just because something is legal it doesn't necessarily mean that it is safe. The fast majority of people use drugs because it makes them feel good. They help them in social situations, they help them to party, that's why they use them."
But he did admit the drug was appealing because you do not have to buy it from dealers or from criminals.
Earlier this month Joe Kiltie, 19, from Ayr died after a night out with friends. His mother blamed the drug after finding traces of it in his bedroom.
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