An undercover police operation which began with the stabbing of a teenager in an Erith tower block has netted six drug dealers and shut down a crack house.

During Operation Conqueror, an undercover officer was imprisoned in the crack house in Maynard Close, Erith, and forced to smoke a pipe of crack cocaine.

Now the last of the dealers involved are behind bars after admitting conspiring to supply a Class A drug.

Last Friday at Woolwich Crown Court, Charles Mugo and Osman Suleyman, both aged 19, were each sent to a young offenders' institution for two years.

Suleyman was also sentenced to a further 12 months behind bars, to run consecutively, after being found guilty by a majority verdict of falsely imprisoning the undercover police officer.

Mugo and another man, 24-year-old Carl Hall, were cleared on this charge.

Bexley police set up Operation Conqueror after the death of 18-year-old Faridon Alizada, who was murdered in Verona House on the Larner Road estate in Erith, on January 5.

Following the killing, information coming from the public to Bexley police about drug dealing in the borough, trebled.

The six-month operation, which targeted heroin and crack cocaine dealers, involved a specialist police officer going undercover and posing as a dealer.

Altogether, nine dealers were targeted and on April 16, 60 Bexley officers made simultaneous raids on 12 addresses across the borough.

A crack house closure order was made against 22 Maynard Close, the home of Hall, who pleaded guilty at Woolwich Crown Court to allowing his premises to be used for the supply of controlled drugs.

He will be sentenced on October 3.

During the trial on the false imprisonment charge, the undercover officer, "Tom", gave anonymous evidence of how he had visited Maynard Close on several occasions to buy drugs.

On April 2 he wore a hidden microphone and video camera to film the drug dealing, but was accused of being a police officer and threatened with a body search.

"Tom" returned to Maynard Close the following day without the equipment and said he immediately knew something was wrong.

The front door was locked behind him and a dealer called "Stretch" demanded he smoke a pipe of crack cocaine "to show good faith".

"Tom" said he feared for his life and thought "Stretch" was armed and said he had no alternative but to smoke without inhaling.

Hall, who has had a leg amputated because of his drug addiction, claimed the dealers had offered to bring drugs to his house and was powerless to resist them as they turned his home into a drugs den.

He claimed they told him they would "burn down my house with me in it, if I went to the police".

Suleyman, of Pett Street, Woolwich, claimed he had tried to warn "Tom" the situation was dangerous and to just smoke the crack and go.

Mugo, of Blendon Terrace, Plumstead, entered no defence.

After sentencing, Judge Peter Murphy said the court would recommend a commendation for the undercover officer's bravery.

Others arrested during Operation Conqueror and who pleaded guilty to possession of Class A drugs with intent to supply, were unemployed Darren Dixon, aged 28, of no fixed address, who was jailed for three-and-a-half years at Woolwich Crown Court on July 15.

At Woolwich Crown Court on July 24, Mark Downs, aged 41, and Sarah Kennedy aged 31, both unemployed of Grange House, Slade Green, each received a 12-month jail sentence, suspended for two years, and a two-year supervision order while undergoing drug treatment.

Sergeant Ross McKibbin, who led the operation, said it had been "an excellent result which has disrupted the flow of hard drugs into the borough".