Two of the Hatton Garden burglars took part in a multi-million pound heist at a Mayfair jewellers five years earlier, a court has been told.
Posing as workmen, Terry Perkins, 68, and Daniel Jones allegedly broke into Chatila jewellers in Old Bond Street during the August bank holiday in 2010.
They tried to drill into a safe with about £40m worth of jewellery inside and stole £1m worth of jewellery from the showroom instead, jurors heard.
Perkins, from Enfield, denies burglary.
'Premier league crime'
Jones, 59, also from Enfield, entered a guilty plea at a previous hearing.
The prosecution said the Mayfair burglary bore "striking" similarities with the Hatton Garden Raid in 2015 for which Perkins and Jones were each jailed for seven years in March 2016.
That raid was described as one of the biggest in English legal history, involving valuables worth up to £14m.
The reason there were similarities between the two raids was no coincidence, but precisely because "Perkins and Jones were involved in both", Southwark Crown Court heard.
Philip Evans QC, prosecuting, said: "This was, say the prosecution, a premier league crime that required premier league criminals to execute it."
Wearing high-visibility jackets, the pair attempted to break into the safe of the Mayfair shop between 28-31 August, 2010, jurors heard.
Once again, the alarm sounded but only a cursory inspection of the exterior was undertaken.
CCTV showed four men getting out of a van at about 07:00 BST on 29 August and then leaving the jewellers with white containers and bags some time between 21:00 and 22:00.
The burglary was not discovered until 31 August.
A milky fluid was found on the display cabinets that was similar to liquid found on the premises of Hatton Garden Safe Deposit, following the raid during Easter 2015.
A third man, Charles Matthews, 54, of Virginia Water, Surrey, is accused of handling stolen goods from the Chatila burglary, which he denies.
Jewels from the burglary were found hidden in the office of Perkin's long-time associate, Mr Matthews, the court heard.
Officers found a black plastic bag containing 50 diamonds concealed behind a removable ceiling tile in Mr Matthews' office.
The diamonds have an estimated value of £48,750. Two emeralds and a jewelled bangle missing from the store in Mayfair were also found on the premises.
Mr Matthews' fingerprint has been lifted from one of the bags containing the missing emerald, the court heard.
The trial continues.