At the time of going to press, no arrests had been made and no one has been questioned in connection with the crime.
Professional thieves who raided the facility during the Easter/Passover break entered the basement via a lift shaft before drilling into the 2m reinforced concrete walls of the vault with heavy-duty tools.
At a packed press conference on the pavement outside the premises on Thursday April 9, police said the owners of about 70 security boxes raided over the Easter weekend were in the process of being identified and contacted. Forensic teams were examining the scene for clues but police said there was no sign of forced entry.
The flying squad's DCI Paul Johnson said police were called on Tuesday (April 7) at 8.10am and found a chaotic scene: "The vault is covered in dust and debris and the floor is strewn with discarded safety deposit boxes and numerous power tools, including an angle grinder, concrete drills and crowbars."
Jewellers and traders in Hatton Garden used the Safe Deposit to save on insurance costs. A medium-sized deposit box at the vault could cost as little as £300 a year.
Hatton Garden Safe Deposit was also the target of a raid in 2003 in which £1.5m of jewellery and cash were stolen by a thief posing as a customer who emptied deposit boxes.