Scott tells Sky News: "I think that's what the director's cut is - the two and a half hour - that's the truth of it. Because I learned early on, basically from all the films I've done, but also from early days as a commercial maker. Am I communicating and how tight can I be to communicate and say everything I want?"

And it turns out he employs a special technique to ascertain when enough is enough.

"I have something that's called the bum ache factor - you're sitting there going, 'Oh God, there's another hour!' You got to be really sure that you're running a three-and-a-half-hour movie that's actually worthwhile, people get weary.

"When I'm cutting… you're constantly watching out for 'Where are we bending and why is it bending?' Is it because I'm tired or is it because this story's just going on too long?"

Clocking in at two hours and 38 minutes, the shorter version is far from swift, but there are lots of battles to fit in, including Waterloo, Toulon and Napoleon's greatest victory, at Austerlitz in 1805.

Scott admits, "longer can be a disaster," calling it "a natural fault" most directors "wrestle with".

Regardless of length, just making the movie is an achievement. Stanley Kubrick, Charlie Chaplin, Steven Spielberg and Baz Luhrmann all saw their dreams to portray Napoleon on the silver screen shot down.

But Scott, as his reputation suggests, is not a man to be defeated. A notoriously forthright filmmaker, he's also not averse to quizzing his interviewers as they attempt to question him.

Luckily, this reporter appeared to pass the test, correctly answering the question, "Which historic figure can claim the most films made about them?" (Jesus, in case you're wondering).

Napoleon clocks in at second place, with 10,400 books written about him, one for every week since he died, according to Scott.

On tweaking history: 'I don't think it matters'

Of course, there has been a minor fuss about the film's trifling historical inaccuracies (Napoleon watches Marie Antoinette's execution and his troops fire upon the Pyramids - neither of which happened in real life), and a few sniffs about lead actor Joaquin Phoenix's US accent throughout.

Scott cares not a jot: "If he talked in an Italian accent, people would have criticised me. And if he talked in a French accent, they would have criticised the French. So, it's best to just go back to what [Joaquin] was.

"If you're engaged by him, be engaged by him. And I think and I'm fully engaged by anything Joaquin does so I never even question it… I don't think it matters."

Speaking Italian when he arrived in France from Corsica, Scott says Napoleon learnt French in just two months.

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But aside from the debate over how much artistic licence is too much, most UK and US reviews have been positive. The French reaction, however, has been less warm.

'They look for anything that can find fault'

Scott says he's far from surprised.

"I had a major premiere in France with a big room of a lot of important people. Their reaction was very, very, very enthusiastic. So, they're going to look for anything that can find fault, but they always do, I'm used to it."

Luckily, he's of the opinion that "there's only one critic that is worth anything, that's yourself".

And whether it's his inner critic that keeps him working or not, he's certainly not showing any signs of slowing down.

A prolific worker, South Shield's born Scott started out in advertising, where he says he made two adverts per week in his heyday.

He was nearly 40 when he made his first feature film, and now at 85, has 28 under his belt, including Alien, Blade Runner and Thelma & Louise, all of which have made their mark on popular culture.

He's also made numerous TV programmes, and now with his deal with Apple TV+ finished a pilot for them called Sinking Springs, about the drug problem in Philadelphia.

'I feel alive when I'm directing'

Not to be held up by the US actor's strike, he used the time away from shooting to edit the 90 minutes of Gladiator 2, starring Irish actor Paul Mescal, which was already in the can, and now the actors are back at work he'll be wrapping it by Christmas.

As for his next film, he's already cast it, written it, and set it up ready to go, as he says, "I'm always in prep - slightly ahead".

So, at 85, what's the secret to his impressive productivity?

"I love the energy of it. I feel I'm alive when I'm a shooting director… I just love the stress. You've got to embrace stress - if you don't, don't do the job."

As for what gets him up in the morning, he says: "Drive is... You're born with it or not...I have no criticism for anybody who just wants to take a holiday, holiday is not in my jurisdiction. I mean, three days' holiday is fine. Then what?"

With Ridley Scott, the "then what" is the question always on his lips, and like the flawed military genius at the heart of his film, action is the answer to conquering the world.

Napoleon is in cinemas now, before streaming on Apple TV+