This is, after all, supposed to be a summer's day with scenes showing the immediate aftermath of the biggest robbery in the country's history - the Great Train Robbery, which took place in the early hours of August 8, 1963.
"Apparently, it was the coldest August here in history, so we're not detracting too far from 1963," says Luke Evans, who plays chief protagonist Bruce Reynolds.
Despite his unremarkable outfit, a blue boiler suit, the Hollywood actor rolls up to the dilapidated farmhouse looking debonair, his dark hair combed in period style.
Evans's co-stars, Martin Compston and Paul Anderson, have even called him a Cary Grant lookalike.
"That's not bad," says the 34-year old Welshman, laughing cheekily.
His demeanour suits his character, given that Bruce Reynolds was regarded as a charismatic figure.
"He was a super-sharp dresser and had his own tailors. Even when everybody else was slovenly dressed, he always had his tie perfectly positioned. He was the whole package," the actor notes.
The film begins with a previous robbery at Heathrow Airport in November 1962, and then shows how Reynolds assembled and led the gang that targeted the August Bank Holiday mail train from Glasgow, running off with
£2.6million (the equivalent of over £40m today).
"It wasn't supposed to be that amount of money and, while all the other boys were excited about it, Bruce was thinking, 'Well this is all well and good, but how are we going to get the money back to London and get it clean?' He was always one step ahead of the rest of the team."
The drama also details the fall-out from the coshing of the train driver, Jack Mills, and why, within days of the robbery, the gang's safe house had to be evacuated and all those involved were forced to go on the run - some, for the rest of their lives.
Reynolds fled the UK with his wife and son, but in 1968, the law caught up with him and he was jailed. Years later, he wrote a tell-all book, The Autobiography of a Thief: The Man Behind The Great Train Robbery.
"In Bruce's book, he talks about how much he liked the planning part, guessing what the police would do and thinking of all the contingency plans," says Evans.
"I can imagine them questioning and examining all the areas for hours and hours, because Bruce wasn't very good at failing. He wanted to be the best and, the only way you can be the best, is if you're very thorough."
A second film called A Copper's Tale, detailing the police hunt and starring Jim Broadbent, will air the following night, which Evans says is an inspired idea.
"There were some fantastic characters on the police side and, in a way, the robbers mirrored the coppers. Some of them were leaders and some of them were followers, so when it goes out on the screen, people will be able to see the similarities between the both sides."
Evans would've loved the opportunity to meet Reynolds, but fate dealt its hand and the robber passed away before it could be organised. (Reynolds died, aged 81, in February.)
"He could've been many things, because he was very capable in many different fields, but he chose to be a criminal - and he became one of the best," says the actor, who'd been researching the role for a few months when the death was announced.
"It felt like I knew him slightly," he adds. "Bruce was a great writer and he was always very adventurous in his ideas, a visionary - and
I liked that about him. I saw a bit of myself in the young Bruce."
While he makes it clear that he doesn't think the robbers should be admired ("At the end of the day, they broke the law,") he admits the reaction they got from the public was intriguing.
"People were in a moral dilemma when asked what they thought. They were a bit like: 'It's amazing they got away with it, good on them!' It seemed like they'd done the impossible, so I think it did capture the heart of the nation."
And not only here but across the world.
"I went to LA just before I started this and I was on a set talking to American actors, and they'd heard about it, they knew about this story!" remarks Evans.
Since graduating from the London Studio Centre, the performing arts college he won a scholarship to, Evans has focused on film, starring in the likes of Clash Of The Titans, The Three Musketeers and Immortals, but having seen the great drama being produced for TV, he he "wanted to be part of it".
"Then this came along and I thought the script was brilliant," he says.
n A Robber's Tale airs on BBC One on Wednesday and A Copper's Tale airs on Thursday.