The operation focused on the Caia Park estate in Wrexham

They were given cash to buy drugs as part of "Operation Quantity," and the dealers were filmed doing business.

As a result of the officers' evidence, 17 people were arrested in a series of dawn raids across Wrexham, the court heard.

All have been sentenced except one, who is expected to be dealt with on Friday.

Another man had been sentenced previously.

The operation took place during October, November and December of 2006 and focused mainly on the Caia Park area of Wrexham.

The two officers in question should receive the personal commendations of this court Judge Merfyn Hughes QC

The two officers known only as Shelley and Gavin, were brought in from outside forces to mix with the town's addicts.

Richard Edwards, prosecuting, gave details of the meetings that had taken place as the officers were introduced to people who were willing to supply them with class A drugs.

Sentencing the 13 men and two women, Judge Merfyn Hughes QC said they had all been involved to a greater or lesser degree in the supply of drugs.

He spoke of the degradation, suffering and the death that drugs brought to addicts.

Courage

Judge Hughes highlighted the careful planning of the operation and said those responsible should be commended.

The fact that each one of the defendants had pleaded guilty was a measure of its success, he said.

"Further, the two officers in question should receive the personal commendations of this court," he added.

"This kind of work regrettably must continue in the future.

"The position is, however, that without officers who have the courage and determination to put themselves at great risk, this kind of operation would not be as successful as this one was."