The producers of Peaky Blinders are being investigated over alleged breaches of Covid-19 restrictions.
Crew members say they were placed at risk after a staff member allegedly continued to work on set despite testing positive, The Guardian reported.
The Birmingham-based gangster series is currently in production for its sixth and final series.
Filming for the BBC show was suspended earlier this week, with a spokesman for the show saying at the time it was because of “a false positive test for a member of the crew”.
But crew members claim that filming carried on for a few hours after the result until another member of the staff discovered and halted filming.
A second test from the infected crew member came back negative and shooting resumed.
Union Bectu confirmed it was investigating the allegations.
Spencer MacDonald, one of its national secretaries, said: “The safety protocols are in place to create a safe working environment for cast and crew.
“Therefore the production should have informed everyone immediately and stopped filming.
“Otherwise a lapse like this could have contributed towards the spread of the virus. We are currently waiting for the production to respond.”
Some crew are said to have reacted angrily to the discovery, asking why filming was not shut down immediately after the first test result.
One alleged that some of those working on set with him did not know that the crew member had tested positive with some reportedly reluctant to continue filming on Peaky Blinders.
Although broadcast on the BBC and Netflix, the show is co-produced by two companies: Caryn Mandabach Productions and Tiger Aspect.
A spokesman for the show declined to reveal who had the test, for “data protection” reasons, and said: “Filming was stood down on Peaky Blinders because of a false positive test result for a member of the crew.
“ In line with protocol, this person took an NHS test and anyone who came into contact with them self-isolated – the safety of our team on Peaky Blinders is of paramount importance. The NHS test came back negative and filming resumed on Thursday.”
The show has been critically acclaimed since its inception in 2013 with its latest episode reeling in 3.9 million viewers across the UK.