A young couple were repeatedly stabbed as they sat on a bench in Haringey, north London.
The couple were sitting on the bench in Downhills Park Road when they were approached by two men who demanded the man's phone.
When they tried to move away, both men produced knives and the man was stabbed repeatedly in the back.
His 21-year-old girlfriend suffered a cut to her hand in the attack.
The man remains in a serious but stable condition in hospital, police said.
The suspects are described as black, aged about 20 and both were wearing scarves across their faces.
Police are appealing for witnesses to the incident, which happened around 6pm on Wednesday, to contact them.