Southwark Police have arrested a man who attempted to stab officers and supermarket staff with a pair of scissors.
Plain-clothes officers from Southwark Crime Squad were in The Cut at about 6.30pm on Bank Holiday Monday when they came across an attempted robbery at Sainsbury's Local just across the borough boundary in Lambeth.
A man was threatening staff with scissors and attempted to stab a security guard when he intervened.
He then also attempted to stab officers when they arrived.
The suspect fled the scene and, after another attempt to stab an officer, police used CS spray and the man was arrested on suspicion of attempted murder and robbery.
He is currently in custody at a south London police station.
No officers or members of the public were injured during the incident.