Almost half a billion pounds every year would be taken out of health spending to help young drug addicts beat their habits under Conservative plans.

Shadow home secretary Oliver Letwin said getting young heroin and cocaine addicts into intensive treatment was the only serious way to cut crime.

The move would also mean "huge savings" to both the NHS and the criminal justice system in the medium term, said Mr Letwin.

The announcement came as Tory leader Iain Duncan Smith said law and order in the UK was on the "verge of collapse".

'Empty gesture'

Reforming the criminal justice system is expected to the flagship measure in Wednesday's Queen's Speech.

Visiting a drug treatment centre in west London on Tuesday, Mr Duncan Smith those reforms would be an "empty gesture".

Nuisance behaviour is a prime public concern

"A crime is committed every five seconds, detection rates have fallen by 28% and criminals have a 97.5% chance of not being caught and convicted," he said.

"The slogan 'tough on crime, tough on the causes of crime' was a good one.

"Unfortunately, it has come to nothing because of the government's utter failure to deliver."

Labour Chairman John Reid said tackling anti-social behaviour and improving public services would be at the heart of the Queen's Speech.

"We have to get a criminal justice system which becomes a victim's justice system which is seen to be on the side of the victim and not on the side of the criminal," said Dr Reid.

Drugs is becoming a key focus of Tory crime policy and Mr Letwin condemned the UK's "pathetic response to serious addiction".

Treatment numbers

At last month's party conference, the Tories said they wanted to give young drug addicts a choice between getting treatment or facing court action.

The Conservatives are launching a consultation paper on their drug policies on Tuesday.

As they try to move away from talk of division after Iain Duncan Smith's "unite or die" warning, the party wants to get on with looking like an alternative government.

Oliver Letwin: Huge savings can be made

In an official parliamentary answer from the Home Office, Mr Letwin was told there were 118,000 people "in contact" with treatment agencies.

The Department of Health says there are about 3,000 places available on residential treatment courses, as well as inpatient "detox" places.

But Mr Letwin suggested the country needed about 20,000 residential places.

'Colossal cost of drugs'

Mr Letwin said the UK should aim to mimic the Netherlands, where the average age of heroin and cocaine users was rising by about a year every year.

"In other words, hardly anyone is joining the queue," he said.

The shadow minister said it would cost �460m a year to deliver on his aim of making every young heroin or cocaine addict to go on an intensive treatment course.

That money could best come out of the healthcare budget, he said, and could produce "huge savings" in the medium term.

"It is colossally expensive what's going on at the moment - people who are on heroin and cocaine and are problem users of it are driven into acquisitive crime," said Mr Letwin.

Research for the Home Office recently suggested drug abuse was costing Britain a total of �18.8bn a year.

The Tory drugs policies have been cleared by the party's Treasury team, which is anxious not to make spending pledges that could be hostages for fortune at the next election.

Cutting crime

Mr Letwin said Chancellor Gordon Brown was plugging a lot of money into the NHS, although it was being badly used.

"Let's use some of it this way because we'll get the savings in the long run.

"In the meantime, it's the only way we can go to make a serious impact to the level of youth crime and the level of crime in general."

Some drugs agencies have questioned who is going to staff the extra treatment courses envisaged by the Tories, but Mr Letwin said it was a long-term programme.