Twenty-three people have been arrested in an armed raid on a former Rastafarian temple in south London.
The site was the headquarters of the UK's Rastafarian community
About 250 officers targeted the 32-room property in St Agnes Place, Kennington, in the early hours.
Police said the site, seen as the focal point for the UK's Rastafarian community, was receiving up to 600 visits a day, mostly for drugs.
Kilogrammes of cannabis, some crack cocaine and ammunition were found inside, said police.
The search of the property is expected to take up to three days.
The site had been under 24-hour surveillance for the past six months, police said.
Lambeth Borough Commander Martin Bridger said there were different rooms for different drugs.
"If you were there to buy cannabis, you were probably directed to one room," he said.
"If you were there to buy crack cocaine, you were directed to another room."
Ch Supt Bridger said he had not witnessed drug dealing on such a scale in all his 30 years as a police officer.
Evidence was gathered against a core of about 12 people suspected of drug dealing since the operation began last October.
An explosive which goes off with a large bang, was used to distract those inside the premises as officers filed in.
It made some residents believe they had heard gun shots, but a police spokesman said no weapons were used.
Reggae legend Bob Marley is believed to have been a frequent visitor to the temple, thought to be London's oldest squat, in the 1970s.
"It was a place of worship," said Commander Bridger.
"It's the headquarters for the Rastafarian community for the UK, let alone Lambeth, and we're proud of that.
"But the temple's managers said it had been taken over by drug dealers and was no longer being used as a place of worship."
Lambeth Council leader Steve Reed said the building was due to be demolished and worshippers would be offered an alternative site.
"I would like to make it clear that this is not an attack on our Rastafarian community - this is an attack on drug dealers and criminals," he said.
He said the police operation marked the launch of the borough's "get tough" policy on drug dealing.
"We're going to name and shame people who are caught buying drugs on our streets," he said.
"We will write to their employers, we will publish their pictures in the local newspapers."