Filming on the fifth season of The Crown is currently taking place around the UK, with the valuables being taken from three vans in Doncaster, South Yorkshire, on Wednesday night.
As well as “precious gems” and silverware, The Sun has reported that among the items stolen was a replica of a rare Fabergé egg that was to have been used in a scene featuring Imelda Staunton as Queen Elizabeth II.
Netflix confirmed on Thursday that the robbery had taken place, but said they did not anticipate it affecting their filming schedule.
A spokesperson said: “We can confirm the antiques have been stolen and we hope that they are found and returned safely.
“Replacements will be sourced; there is no expectation that filming will be held up.”
South Yorkshire Police later claimed that “all existing lines of inquiry” had now been “exhausted”.
A spokesperson explained: “Police were called at 4.30pm on Wednesday 16 February following a report of theft from vehicles at Pastures Road, Doncaster.
“It is reported that three vehicles containing props used in film and TV were broken into and a number of items taken.
“Officers investigated the incident but all existing lines of inquiry have now been exhausted. The case has been filed pending any new lines of inquiry.”
The fifth season of The Crown is set to debut on Netflix later this year, with Oscar nominee Imelda taking over the lead role in the show from Olivia Colman.
Also joining the cast for its final two series will be Lesley Manville, Elizabeth Debicki, Sir Jonathan Pryce and Dominic West.