Police described the two robbers as "extremely dangerous"
A man has been arrested in connection with a robbery at a central London jewellery shop in which items valued at £40m were stolen.
Police said the 50-year-old was arrested by officers outside a home in Ilford, east London. He was later released on bail.
Details of the arrest were only released on Wednesday.
The robbery, carried out at Graff jewellers in New Bond Street, was Britain's biggest gem heist.
Two men with handguns threatened staff in the raid on 6 August before taking 43 items.
No-one was hurt, but a female employee was dragged outside by the pair who fired a shot into the ground to warn off pursuing members of the public.
A Metropolitan Police spokesman would not confirm why it took two days before the force released details of the arrest.
He said: "Suffice to say it was operational reasons."
The Met said the arrest was made after police searched several houses.
The spokesman said it took several days for the value of the items taken to be confirmed because the firm's insurance company was still assessing the loss.
Police are following up several other leads.
The £40m haul is exceeded only by the £53m raid on a Securitas depot in Kent in 2006.
The stolen jewellery included a pair of white round diamond double-hoop earrings, a yellow diamond flower necklace and a platinum white Marquise diamond ring.