A police officer was threatened with a shotgun after chasing a suspect into an alley in Anerley.
Two officers were in plain clothes and carrying out patrols last night (June 28) at around 11.30pm when two men on a moped approached them.
The two moped riders appeared to realise they had met a pair of police officers and fled.
One officer chased a suspect into an alleyway in Seymour Villas, only to be faced by him wielding a shotgun.
The man did not fire any shots and instead ran off.
A loaded shotgun was later found in the alleyway along with a knife.
The second suspect had jumped back onto the moped and drove it directly at the other police officer.
The officer swung his baton as the driver sped towards him, knocking the suspect off the moped.
The youth then ran off in the direction of Elmers End, where police lost track of him.
Helicopters and police dogs were brought out as police tried to find the two suspects but they could not be located.
The two men were described as black and between 16 and 20 years old old.
The black Honda moped was recovered and found to have false number plates.
Detective Inspector Ed Facer, the investigating officer from the Met Police's Trident unit, said: “This was a very serious incident with two police officers threatened.
"It was incredibly lucky given the circumstances that they were not badly injured.
“We would appeal for any witnesses to what happened or who saw the suspects making off or anyone else with information to please contact us as soon as possible.
“These are dangerous individuals who were out that night heavily armed with a loaded shotgun and a knife. We need to take them off the streets.”
Chief Supeintendent Chris Hafford, borough commander for Bromley, said: “This was a very worrying incident for my officers who acted with the utmost professionalism and bravery in a difficult situation.
“Both officers were threatened, one with a shotgun which must have been terrifying. "I commend their actions and would urge to public to come forward with any information that could help identify the suspects.”
Any witnesses, or anyone with any information, should contact Trident on 020 8247 4863, or contact police via 101 or Twitter @MetCC.