As widely reported last month, it was revealed the items had been taken from its collection over many years. On August 16 the museum said the theft was the subject of an ongoing investigation by the Metropolitan Police as well as an independent investigation that it had launched.
Now the museum has revealed that 60 items have been returned and a further 300 have been identified and are due to be returned.
The museum revealed it is working with a team of recovery experts including James Ratcliffe, director of recoveries at Art Loss Register, and Lynda Albertson at Association for Research into Crimes against Art.
It has also launched a museum webpage detailing some of the types of objects missing.
The page includes photographs and descriptions but not of the actual items missing. Instead it shows examples of similar pieces of jewellery to those that have been lost.
Although the museum webpage does not list the missing items themselves, more detailed descriptions of the outstanding jewellery pieces have been recorded on the Art Loss Register database which can be accessed by those paying for its service including dealers and auction houses.
Some specialists have argued it would be best for the museum to make the exact descriptions of what is missing publicly available, however the museum and ALR have stood by their strategy.
James Ratcliffe, director of recoveries at the ALR, said: “The British Museum’s approach has carefully balanced the need to provide information to the public to assist the recovery efforts with the fact that providing too much detail risks playing into the hands of those who might act in bad faith.
“We are delighted to provide our assistance on a pro bono basis to the excellent team at the museum to support their efforts.”