There’s a moment early on in Glorious 39 when an elderly gent played by Christopher Lee warns a teenage relative who is looking into their family history that ‘it’s not always a good place to go, Michael, the past.’ Once the story unravels, we see exactly why some stories are best hidden. It’s a statement but that could just as easily have come from naysayers of writer and director Stephen Poliakoff’s work. Yet, while much of the 56-year-old’s back catalogue (Shooting the Past, The Lost Prince, Perfect Strangers) has explored the hidden truths in the pasts of families and societies, it has never been a trawl into the archives for the sake of it, instead enlightening the present by keeping a handle on past deeds.

For Glorious 39, Poliakoff has dipped into the weeks before and following the outbreak of World War Two, when the talk among the British aristocracy was for the need to appease Hitler and stay out of any continental conflict. Into that mix, Poliakoff throws in an actress, the adopted Anne (Romola Garai) whose father (Bill Nighy) is a high-ranking politician but whose connection with the secret service and their pernicious campaign in silencing critics of Chamberlain’s policy is unclear. With Anne trying to find out exactly who is behind a series of deaths to close friends, the film is paced almost like a conventional thriller, running somewhat contrary to the stately feel of Poliakoff’s small screen output.

‘I have always liked suspense stories and thrillers,’ he notes. ‘Obviously we have Hitchcock, while one of my favourite films is Rosemary’s Baby. We’re not a huge country like America, but there has to be more at stake than a heist that goes wrong or money buried behind the chimney, and I was extraordinarily interested in what a close run thing it was that we didn’t do a deal with Hitler. Anne doesn’t know who’s on her side and who’s betraying her and I wanted to get across a feeling of a world falling apart where people once felt safe and secure.’

If the people of Britain experienced unease about impending upheaval, just think how the pets of the land must have felt, not able to stay with their masters, who were heading out to the countryside or down into bomb shelters, and being systematically put down. ‘It was something I stumbled upon when I was researching the film and I was so grabbed by it. One book described the piles of dead animals on every high street in London so while you clip clopped to the post office you had to pass these dead cats, dogs, rabbits and budgies. It must have been so horrific in reality, but was also such an eerie harbinger of what would have happened if we had become a Vichy style state.’

While Glorious 39 is being trumpeted as Poliakoff’s return to cinema (his big screen adventures from the 90s include Close My Eyes and Century), and with him having recently spoken out at the ‘Kafkaesque’ and ‘Orwellian’ procedures within BBC committees, he still hopes to write again for the corporation. ‘There’s obviously a lack of money all round but drama is still incredibly popular and one of the defining things on television and therefore in our culture.’

Glorious 39 is on selected release from Fri 20 Nov.