A bungling crook used a knife to cut his way into a convertible sportscar parked in Mayfair before making a failed attempt to drive off in it in broad daylight.

Members of the public pass by as the brazen thief slashes a large hole in the roof before jumping inside the Porsche.

As he does so, the man triggers the alarm of the car, which was parked on Mill Street yards from Regent's Street and Oxford Circus.

After a short and unsuccessful attempt to start it, he exits through the gash in the roof, before bunny-hopping on to its large spoiler and bouncing to the ground.

He then slowly walks from the scene in full view of a CCTV camera.

At one point in the clip, a worker, who is not shown, places a "trip hazard" sign in the street as the attempted theft is taking place.

The strikingly clear footage, which captured the whole incident, was released on Wednesday by the Metropolitan Police in a bid to identify the suspect.

A Scotland Yard spokesman said the incident happened on September 29 at about 7.45am, 20 minutes before a second Porsche - a Cayenne - was targeted on the nearby Carlos Place.

A man matching the description of the one caught on CCTV used a five-inch lock knife to scratch the sportscar and damage the lock in a second abortive attempt to steal a car, police said. The total value of damage caused is unknown.

Detectives believe the same man was behind a robbery at JD Sports on Oxford Street shortly before 11am on the same day.

The suspect, described by police as a 6ft-tall black man in his 20s with black hair and a dark beard, threatened staff with a lock-knife when they challenged him as he tried to leave the store with stolen trainers, a sports top and tracksuit bottoms.

At the time of the incidents, he was wearing a blue puffer jacket, bleached jeans and agrey beanie hat, police said.

Contact police on 101 quoting image 191011 with any information.