A would-be thief has been caught on camera cutting open the roof of a Porsche and trying to drive the convertible away in front of passers-by in the street.
The man can be seen peering through the windows before taking a folding knife out of his pocket and slicing a hole in the top of the car, which was parked on a road in Mayfair, London.
He then climbs in to the red motor, setting off the alarm, and tries to drive it away.
When he fails to get the engine started he climbs back out of the hole, jumps on to the boot and wanders off down the road.
The audacious attempt took place at around 7.45am in Mill Street in full daylight and was apparently witnessed by several people, who can be seen walking past in the footage.
Around 20 minutes later someone tried to force their way into another Porsche parked in the same area, police said.
"At 8.05am on the same day, police were called to reports of grey Porsche Cayenne scratched and the door lock damaged whilst parked on Carlos Place, Mayfair," a Met Police spokesman said.
"A man matching description of the man who broke into the red Porsche was seen to take out a lock knife with a 5inch blade and try to gain entry into the vehicle."
Later the same morning, at around 11am, there was a robbery reported at JD Sports in Oxford Street.
"A man, believed to be the same suspect, was seen trying to leave the shop with stolen trainers, a sports top and tracksuit bottoms," the Met spokesman said.
"When staff challenged the man he threatened them with a lock knife."
He added: "The suspect is described as a black man in his 20s, 6ft tall with black hair and a dark beard. He was wearing a blue puffer jacket, white jeans and a grey beanie hat."
The incidents all occurred on September 29 and police have released the CCTV today in a public appeal.
Anyone with information can call the Met Police on 101 or Crimestoppers on 0800 555 111.