The new series of Silent Witness will see the Lyell Centre encounter an "extremely potent nerve agent" – in a storyline with echoes of the real-life 2018 Novichok poisonings in Salisbury.
Speaking on set during filming, Richard Lintern (who plays Dr Chamberlain) revealed: "I investigate someone’s house where someone has been murdered in a fairly brutal and bloody way. And it only becomes clear later on in the investigation that there’s a connection with the potential for there to have been a nerve agent involved.
"And various characters here get involved in the potential contamination with the nerve agent."
This could mean danger for Dr Chamberlain and his colleagues Dr Nikki Alexander (Emilia Fox), Dr Jack Hodgson (David Caves) and Clarissa Mullery (Liz Carr).
"Obviously, it’s an extremely dangerous – it’s a specifically dangerous situation for forensic pathologists to be in, and one that you don’t necessarily identify straight away," Lintern said. "So you might end up on the scene, and only realise hours later, or 20 minutes later – crucial minutes – that you should have been in one of these protective suits."
He added: "There's a concomitant military connection. When you think about the only places in the country where such things can be created, or whether technology and power exist to create them – our military establishments like Porton Down, or various other ones. The story goes into that area."
As for whether the nerve agent is related to Russia, Lintern would only say: "As soon as you’re in the world of nerve agents, it would be foolhardy to rule out a potential Russian connection. Whether there’s one in our programme or not, I can’t tell you."
Viewers will be familiar with nerve gas poisonings and the dangers of contamination, after the Salisbury poisonings hit the headlines in 2018. On 4th March, a former Russian military officer and double agent called Sergei Skripal and his daughter Yulia Skripal were poisoned with Novichok in the English cathedral town of Salisbury.
But there were three more unintended victims: a police officer was exposed to the toxic agent at Sergei Skripal's house and had to be taken to intensive care, while a British couple who had been visiting Salisbury later had contact with remnants of the Novichok. One, Dawn Sturgess, died in hospital.
The real-life incident is also the subject of an upcoming BBC drama, Salisbury, starring Rafe Spall and Anne-Marie Duff.
Silent Witness returns on Tuesday 7th and Wednesday 8th January 2020 at 9pm on BBC One