Detectives are investigating possible links between the attack and a spate of "Rolex robberies" on the rich and famous. Actress Britt Ekland, Formula One boss Bernie Ecclestone and chef Anton Mosimann are among a string of celebrities who have fallen prey to gangs in central London. Since the beginning of the year, 160 high-value time pieces have been ripped from victims.
In this latest attack, Mrs Scott was watching television at her son Ridley's Hampstead Heath home on Wednesday last week when two men broke in and grabbed her jewellery. She struggled with the thieves who eventually managed to yank the watch free.
The burglars then turned on a nurse and Mr Scott's ex-wife, who were in a nearby room, punching one of the women and threatening to kill them should they make a noise. They were forced to hand over rings and a necklace before managing to set off an alarm.
A Scotland Yard spokesman said yesterday: "We can confirm we are investigating a burglary in the Hampstead Heath area." He said it was too early to say whether the incident was connected to earlier robberies but "we are keeping an open mind about a possible link".
Last month, Scotland Yard revealed that undercover police wearing expensive watches were being sent out as decoys to try and tackle the robberies.
Ridley Scott, 61, whose list of blockbusters include Blade Runner, Alien and Thelma and Louise, was believed to have been filming abroad at the time. He co-owns Shepperton Film Studios with his brother, Tony, also a director whose credits include the film Top Gun.
Earlier this year, Miss Ekland was left bleeding in a Chelsea supermarket after a robber ripped her pounds 10,000 diamond watch. And in May, the wife of motor racing boss Sir Frank Williams lost pounds 100,000 of jewellery and a top-of-the range BMW after being mugged at knife point outside her apartment.
Meanwhile, in another similar incident, Sir David Lean's widow disturbed a burglar at her Kensington home in the early hours of last Friday. Lady Lean, 60, wife of the Lawrence of Arabia director, was unhurt but lost silverware in the burglary.