A marauding gang of violent robbers on e-bikes surrounded their victim then knocked him to the floor and brandished a huge ‘Rambo knife’ before snatching jewellery worth £43,000.
Masked thugs gathered around the victim and a friend as they stood by a sports car with an open door, before launching a ferocious attack and threatening witnesses who tried to help.
They stole his Rolex watch worth £25,000 and two diamond rings worth £9,000 each as he lay on the ground reeling from the assault while shocked passers-by looked on.
Attackers fled the scene of the robbery, on November 21, 2020, at 7.30pm, on their bikes.
Security at The Mayfair Hotel, Stratton Street, tried to intervene in the attack as the men fled.
Police said the victim was left shaken from the attack but did not suffer any serious injuries.
CCTV footage of the violent robbery showed one member of the gang waving a huge knife.
Around 40 minutes beforehand they were on CCTV in Brompton Road, near Harrods, where they unsuccessfully trawled the streets for potential victims before moving on to Mayfair.
Suspects wore face coverings and masks, and the attack took place during the pandemic
But detectives used CCTV and mobile phone data to identify the four attackers.
Brothers Alan Kelly, 27, and David Kelly, 37, Corrie Moroney, 29, and Lewis Sokhi, 28, were jailed for a total of almost 39 years after pleading guilty to robbery at an earlier court hearing.
Alan Kelly was jailed for 10 years and nine months, while his younger brother David received a nine-year and eight months prison sentence.
Moroney and Sokhi were both handed a sentence of nine years behind bars.
Judge Philip Brook Smith QC also banned all the defendants from using e-bikes after their release under a Serious Crime Prevention Order.
DC David Reed said: "Targeting violent crime is the absolute top priority for everyone in the Met, so I am very pleased to see these sentences handed down today. We’re determined to keep the public safe by disrupting and deterring high harm offenders.”
He added: “The results today are a clear warning to anyone else concerned in such offences that whatever tactics you use, the Met Police will investigate you, we will find you, and we’ll do everything in our power to make sure you go to prison.
"This was a truly horrible experience for the victim who was just going about his evening when he was attacked.
“He no doubt feared for his life. I’d like to thank him for supporting us through the investigation and judicial process."
Alan Kelly was also convicted of conspiring to throw a category A banned item into a prison, after he was seen throwing a package into HMP Pentonville last March.
The same charge for Moroney was left to lie on file, the Met Police said.