Detectives from Barnet have released moving footage of a commercial robbery that took place at Marks and Spencer's, Mill Hill.
Just before 06:30hrs on 27 November 2017, two suspects entered the store.
The masked robbers herded staff into an area of the food hall and one suspect, armed with a knife, tied up staff using cable ties.
The second masked suspect took a staff member to the tills where she was forced to open them to allow the robber to remove cash.
The suspects then left the store via the rear doors walking along The Broadway toward Hale Lane and Bunns Lane.
They stole £200 from the store.
Detective Constable Dan Levy, of Barnet CID, said: "This was a frightening experience for store staff at the scene.
"The suspects put the victims in a brief, but highly threatening situation in order to steal £200.
"It is very important that we identify and apprehend these suspects as quickly as possible and I urge anyone who knows them or has information to come forward."
Anyone with information should call Barnet CID by dialling 101, tweet @MetCC, or call Crimestoppers anonymously on 0800 555 111.