Police said inquiries into the raid were continuing As many as 70 deposit boxes were opened during a raid in London's jewellery quarter, police have said.
Burglars gained entry to Hatton Garden Safe Deposit over the Easter weekend. Scotland Yard was alerted on Tuesday.
Officers said a "slow and painstaking process" of forensically examining the scene was under way.
Ex-Flying Squad chief Roy Ramm has said he "would not be surprised" if the jewellery stolen during the raid was worth as much as £200m.
The Met, which has not yet commented on the worth of the jewellery stolen, said it was "photographing the scene and recovering exhibits in meticulous detail".
It said the burglars used heavy equipment to break into a vault used mainly by jewellers and gold dealers.
A spokesman said: "Officers are working closely with Hatton Garden Safe Deposit Ltd to establish the identities of those affected.
"Police will be contacting victims directly as and when they are identified."
Police forensic officers have been into the vault as part of the investigation Mr Ramm told BBC Radio 4's [Only registered and activated users can see links. ] programme: "There's a sort of old-fashioned audacity about it.
"The amount of money and the goods that are taken is never fully revealed... and there's a good chance that not everybody would declare.
"I would not be surprised, given where this one is in Hatton Garden, if £200m is around about the amount stolen."
Officers said heavy cutting equipment was used to break into the boxes in Hatton Garden Norman Bean, who had a diamond ring and bracelets stored at Hatton Garden Safe Deposit, said he was told the burglars accessed the vault via a lift shaft.
"They went down the lift shaft, made a big hole in the wall, got into the safe deposit and I think they drilled into the boxes.
Hatton Garden: London's Jewellery Quarter
- Hatton Garden is situated between the City of London and the West End near Holborn
- The area is well known for its diamond and gold trade
- [Only registered and activated users can see links. ] estimates there are about 300 businesses and more than 55 shops specialising in jewellery - the largest concentration of jewellery retailers in the UK
- The term "jewellery quarter" dates back to medieval times when certain streets were dedicated to specific trades
"They could have been there all weekend, who knows? It's disgrace, it's like something out of a film," added Mr Bean.
Michael Miller fears he has lost £50,000 worth of jewellery Michael Miller, a jeweller from Knightsbridge, said he "felt sick" at the prospect of losing up to £50,000 of uninsured jewellery and watches.
He said a £5,000 he bought for his son on the day he was born might have been stolen and he felt "dismay, shock and disbelief" when he heard the news.
Diamond jewellery expert Lewis Malka, who works in Hatton Garden, added: "With the robbers having probably four days over the Easter weekend, there's a good chance that they went through everything."
London jewellery robberies
- In July 1987 the Knightsbridge Safe Deposit Centre suffered what is thought to be one of the largest robberies in history. Two armed robbers asked to rent a safe deposit box and, after being shown into the vault, produced guns and made off with an estimated hoard of £60m. Valerio Viccei was sentenced to 22 years
- In 2003 jewellery, cash and valuables worth an estimated £1.5m were stolen when a criminal, posing as a customer, emptied a number of boxes at the Hatton Garden Safe Deposit company
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