Daniel Jones admitted last February to burgling the Chatila jewellery shop in Old Bond Street, which made pearl and diamond earrings for human rights lawyer Amal Alamuddin’s wedding to actor George Clooney in 2014.
The 63-year-old, from Enfield, north London, failed to drill into a safe containing jewellery and gems worth £40m during the 2010 August bank holiday.
Instead he made off with £1m in stock and £45,000 in cash, which staff only realised after opening the shop on Tuesday 31 August at 9.30am.
On Thursday Jones was sentenced at Southwark Crown Court to three years in jail which will run concurrently to the seven-year jail term he is already serving for the Hatton Garden raid.
In the Chatila raid, detectives found the lift doors on the ground floor had been forced open and two ladders used to gain access down the lift shaft to the basement.
He made a hole in the lift shaft wall to get into the rest of the basement and forced open a metal gate which was bolted over the lift doors.
The hard drive from CCTV cameras was stolen and the controls for both alarm systems were forced open.
He grabbed the £1m in stock after forcing open display cabinets in the main showroom.
Five years later he played a leading role in drilling a concrete vault to steal jewellery, gems, gold and cash from safe deposit boxes in east London’s jewellery quarter.
Originally police said the Hatton Garden gang stole £14m worth of property.
A new figure of a £29m loss emerged at a hearing last year in which prosecutors were trying to get gang members to pay back what they stole.
Detective Chief Inspector Mark Bedford, of the Met’s organised crime command, said: “I am very satisfied to have secured this sentence against Daniel Jones who believed he had escaped justice for his involvement in this offence.
“This result was achieved through the dedication and determination of Flying Squad officers to ensure those responsible for such audacious offences are tracked down and brought to justice.”