Two drug addicts have been jailed for a total of 11 years for hijacking luxury cars, including one at Sainsbury's in Ealing Broadway.
Gary Grey, of Nyrony Road, Shepherd's Bush, carried out the carjackings with his partner in crime Joe Wegener, of Chiswick, to feed their drug habits.
In one incident the pair, who are both 24-years-old, beat up the owner of a £30,000 Mercedes who resisted their attack.
They then drove off in his car from an Asda car park in Alperton last October.
Several weeks later at Sainsbury's in Ealing, Wegener, with another man whose identity is unknown, hijacked a BMW just as the owner was unlocking the door.
The thieves struck on November 1, as the owner, Dirk Hazell, unlocked his car, then he jumped into the driving seat, after his accomplice told Hazell he was armed with a knife.
He car had a tracker in it and was traced to Fulham, where crucial fingerprint evidence was also found.
Most of the carjacking took place in supermarket car parks.
At Isleworth Crown Court on Friday Judge Sam Katkhuda told Grey and Wegener that people had the right to park their cars in public places without being subjected to violence and having the cars taken from them.
Judge Katkhuda said: "You grabbed Mr Wells from behind with the intention of taking his Jaguar.
"He managed to shake you off and call the police.
"Soon afterwards you attacked Mr Al-Nahas, knocking him to the ground, demanding his keys and punching him in the face. You drove away in his car.
"He must have felt very helpless being attacked by two people. Violence was used against him and his car stolen.
"It is the duty of the courts to do what they can to impose fitting punishments on defendants who use violence so that people can use the streets in safety."
Both men admitted to charges of attempted robbery of the Mercedes, plus another incident involving a Jaguar.
Wegener further admitted to burgling a Hammersmith flat, stealing computer equipment worth more than £11,000 in September, assault, and robbing Dirk Hazell of a BMW at Sainsbury's on November 1.
He was jailed for six years and Grey, for five years.
Both their counsel said the offences, although serious, were "opportunistic" and motivated by an addiction to hard drugs.