POLICE were facing a race against time last night to find a batch of contaminated heroin that has already left ten North-East addicts seriously ill in hospital.

Detectives on Teesside believe the same batch was responsible for all ten cases - and fear addicts could die unless the heroin is found.

All the victims were taken to the Middlesbrough James Cook University Hospital after suffering respiratory failure.

Police said last night that many more users could be at risk.

So far there is no evidence to suggest the heroin has been deliberately contaminated to cause harm or injury.

Police issued the warning only days after The Northern Echo revealed how schoolgirl prostitutes were offering sex for £2 to feed their drug addiction.

It also came as almost 500 Cleveland Police officers took part in an unprecedented round-up of some of Teesside's most wanted suspects yesterday.

Operation Sabre was launched in a series of early morning raids across Middlesbrough.

The targets were burglars, thieves, drug dealers and hooligans, and 42 suspects were arrested.

But the high profile crackdown has given police no further leads in the hunt for contaminated heroin.

Superintendent Stewart Swinson, Middlesbrough Crime Manager, said last night: "We are extremely concerned.

"Ten people have already suffered and needed hospital treatment. As far as we know, no one has died.

"So far the sufferers from this drug have been confined to Middlesbrough, but supplies could be circulating in other parts of Cleveland and elsewhere in the north."

"It is imperative that addicts avoid this suspect drug. If they are offered it or know about its circulation, we would ask they would alert us as soon as possible."

Heroin is derived from morphine, which is a white powder in its pure form, but is more usually brown due to the presence of additives.

Unscrupulous dealers usually "cut" the drug with powdered milk, talc, curry powder, washing powder and other substances to make it go further.

Detectives say the suspect heroin is slightly darker than normal and is hard to dissolve. It forms a tar like appearance when mixed with citric acid, which is used to break down the drug for easier injection.

Tina Williams, project manager of the Stockton group Parents and Addicts Against Drugs In Communities, said she had not been informed of the drugs alert.

"If they know what the problem is they should be telling us," said Tina, who runs a drop-in centre and support phone line. "We see up to 50 drug users every day and we need this information to try to avoid people over-dosing."

It is understood that warning notices about potentially contaminated heroin have gone up at GP practices which work with addicts.

Four years ago, 40 heroin addicts in Dublin, Glasgow, Manchester and north-east Scotland died after using heroin which was believed to be contaminated with a tetanus-type bacteria.

Hospitals on Teesside say they are ready to deal with any patients brought in showing signs of drug abuse.

Mr Kyee Han, accident and emergency consultant at the James Cook University Hospital, said: "We have protocols in place for looking after any patient affected by drugs misuse. We also work closely with the police if we identify any concerns."

* Can you help? Ring Crimestoppers on 0800 555 111 or Middlesbrough police on (01642) 303126.