A large cannabis factory was found by chance when Sutton police attended a burglary in progress on Sunday.
Officers were called to a house at around 4.30am on reports of a break-in only to find it was filled with a large number of cannabis plants.
Inspector Craig Went of the Metropolitan Police South Area Command Unit said: “The drugs that were being grown at this address are in the process of being seized and will no longer find their way on to the streets of Sutton.
“I would urge anyone with information regarding the supply of drugs to come forward and speak with us.”
The National Police Air Service gave assistance to officers as they chased a suspect running from the scene carrying a large knife.
The man was eventually found hiding under a tree.
Two 18-year-old men have been arrested on suspicion of possession of cannabis and in connection with the burglary.
Inspector Went added: “These arrests highlight the value of a community working with police.
“One phone call to officers led to arrests and the recovery of a large knife.”
There have been similar cases of cannabis production sites of this kind in Sutton recently.
Police discovered nearly 300 cannabis plants at an address in Guy Road in May.
In 2016 two men were jailed for operating a factory opposite Sutton Police Station where plants seized were worth an estimated £270,000 in street value.