IT was one of the most successfu l - and dangerous - police operations of recent times, designed to disrupt the supply of hard drugs in Darlington.

For 18 months, a small band of covert officers from Durham Police became immersed in the murky world of large-scale cocaine and ecstasy-dealing, eventually leading to a series of arrests and convictions.

They infiltrated the circles their prey moved in, regularly making purchases of thousands of pounds worth of drugs, while frequently fearing they could be unmasked at any time.

During Operation Karaman, two officers, known only as Keith and J, were certain their cover had been blown when one of those involved in the drugs conspiracy, doorman Matthew Pybus, told them he believed they were undercover officers.

However, they managed to bluff their way through it and maintain their cover. Sometimes they were taken to remote locations, often in the country, where discussions and deals would take place.

Those involved in criminal activities were also equally paranoid they would be found out by police.

On one occasion, one of the ringleaders, Shaun Robson, showed the officers to a house in Darlington after he told them he been offered a gun outside a pub.

The officers, who said they were interested in the weapon, were then ordered to strip because it was suspected they had recording devices on them or were armed.

A shotgun was eventually handed over for £120. Robson, a former postman, later admitted helping the officers to get the gun, but said he thought it was a "dud".

Another man, Paul Wilson, had his flat in Willow Road, Darlington, placed under surveillance during the operation after it became clear he was dealing drugs.

He later told the officers he wanted "things to calm down" because he feared being found out, and had even noted the registration numbers of cars he suspected were following him.

Those arrested and convicted as a result of the police operation had various roles.

They included Roger Bowers, who sold ecstasy tablets, and Alistair Douglas, who rang one of the officers quoting £25,000 for a kilo of cocaine and £6,250 for 250g.

The officers later paid £7,000 for 250g - the price having gone up. If sold to users, it would have fetched more than £25,000.

Tony Hall, known as Boney, was another dealer the officers came across, who offered drugs on a sale or return basis in exchange for cash up front.

Deals for ecstasy made by the officers included £4,000 for 5,000 tablets and £5,600 for 7,000 tablets.

Had they been sold on individually, profits could have been five-fold.

Locations where deals took place included the former Mick McCarthy's bar, in Duke Street, the car park of the Blockbuster video store, in Grange Road, and the service station at Scotch Corner.

Teeside Crown Court heard that the lengthy undercover operation ended when it was decided the officers could not make any larger purchases, despite repeated attempts.

Some of those eventually arrested quickly admitted their involvement, while others said they had only introduced the officers to drug-dealers as a favour and said the allegations against them were rubbish.

As for the officers, whose painstaking gathering of evidence led to the convictions of those involved, they won praise for their efforts.

Judge John Walford said: "These officers made enormous personal sacrifices and took considerable risks in going about the task which they had been entrusted."