Business cards, pool cars and bonuses for meeting sales targets - not perks for estate agents, but for members of a highly organised gang of drug dealers.

Five members of the gang - all of Bangladeshi origin and living in east London - were jailed for up to six years each on Thursday after admitting the supply of Class A drugs.

Police say the dealers' operation, which was estimated to have made over �2m a year, marks a worrying new trend in drug dealing within the Bangladeshi community in this country.

They were making between �3,000 and �5,000 a day on the sale of heroin and crack cocaine

DI Keith Surtees

The low profile of the operation, involving 12 friends in their 20s who lived on the Hadrian's estate in Bethnal Green, meant they went undetected for six years.

The gang leader Shamshad Ahmed, 28, lived in council accommodation, with his extended family.

Detective Inspector Keith Surtees, from the Metropolitan Police, said it was a sophisticated business.

Expenses

The gang advertised by setting up a fake taxi company and handing out calling cards to punters.

"They would distribute their telephone numbers to prostitutes and other drug dealers so they could expand their business to the point where we think they were making between �3,000 and �5,000 a day on the sale of heroin and crack cocaine," he told BBC Radio Five Live.

Dealers would swallow rocks of crack cocaine to avoid arrest

Mr Surtees said the gang rang a hierarchical system, with organisers paying the "foot-soldiers" a wage and bonuses in cash or drugs if they beat sales targets.

Police logged 3,500 calls to one of the dealer's mobile phones in three months.

The dealers, covered 24 hours a day, seven days a week by working shifts, could also claim petrol and food expenses if they produced a receipt.

DI Surtees said that until the police launched Operation Emu last October, officers had had trouble trying to gather evidence to pin down the dealers for dealing.

Possession

The dealers, carrying drugs in their mouths, would swallow them if approached by police.

"We know for a fact there was one individual, after he was stopped by an officer, who within two minutes regurgitated the drugs he had swallowed and sold them to a punter on the street," said DI Surtees.

"It is very, very difficult to get the evidence against them to prove they are in a sophisticated drugs operation distribution-wise."

If dealers were arrested and caught with drugs , it was usually only four or five rocks of crack and they would be charged for possession for personal use, not dealing.

But the ring was finally smashed by the launch of Operation Emu, part of the Met's Operation Strongbox which provides extra detective support to boroughs in order to target serious crime.

Ahmed, Abdul Alim, 21, Shueb Choudhury, 22, and Abdul Hasnath, 26 were jailed for six years each.

Khalrul Mahmun, 26, was jailed for four-and-a-half years.

Seven other members of the gang have already been sentenced to a total of 14 years.