Home Secretary David Blunkett visited the valleys, which are being rocked by a spiralling rise in heroin and cocaine use and by consequent drug-related deaths and crime.

The extra money comes after Labour politicians lobbied the Home Secretary at the party's conference in Blackpool.

The cash injection will be matched by police to boost the crime-fighting fund by �2m over the next two years.

The disaster of unemployment leads to hopelessness and communities falling apart - drugs throw petrol on that fire

David Blunkett

It will go directly to Operation Tarian - an armed crackdown on the sale by "middle men" in south Wales of cheap narcotics from across Offa's Dyke - jointly run by the region's three police forces.

Police chiefs have said the threat from drugs is the biggest danger facing the valleys.

They say communities are being "ripped apart" by hard drugs and associated crime - and could be destroyed completely if heroin and cocaine are not removed.

Some of the cheapest supplies in the UK are said to be flooding the region from Bristol and Birmingham - police and politicians want to smash those gangs.

Heroin arrests rocketed by 80% in the year to April, according to South Wales Police.

Seizures of heroin in the four months to August equalled those in all of 2000.

Crack cocaine seizures in the same period equalled those in 1999 and 2000 together.

The number of registered drug users increased by 14% in the six months to August.

Rehabilitation delays

Some parents have accused the Welsh Assembly Government of failing their addict children by not providing comprehensive rehabilitation and detoxification programmes quick enough.

In July, the Welsh Assembly Government promised to bankroll the police's drugs crackdown if the UK Government could not stump up cash.

Some valley communities are being 'ripped apart'

It is unclear whether the sum from the Home Office means that pledge still has to be on the table.

Mr Blunkett was made more aware of south Wales' drugs problem at his October meeting with the region's MPs - a delegation led by Labour Rhondda member Chris Bryant.

The home secretary had said the group had "made a good business case".

"This problem is growing," Mr Blunkett said ahead of his visit on Friday, blaming a "failure of investment" under previous administrations.

"In our early years, [the government] was beginning to struggle with this problem without having the resources linked up to policing which would make the difference."

He said he would publish a revised drugs strategy within three months.