I find it hard in these strange times to watch a film without viewing it through the prism of Brexit.

After all, what other reason can there be for making a film now about Churchill? And this is not the Churchill of the Boer War, not the Churchill of Gallipoli, not the Churchill of the General Strike, not the Churchill who lost the election in 1945, in fact there are very few warts in this portrayal of him at all. This is a film about a glorious leader who stood firm while all of Europe fell and the Yankees kept away. So why else, and why not now, if not to give the Brexiters a vision of how the world was and could be again?

For here is the England that the Brexiters so desire. An England with a strong leader, an England King with pomp and ceremony, where the Empire is still ours, still some way from independence, where the underground runs on time and the streets are full of Mary Poppins characters, not Polish bricklayers or Afghan refugees, or Calais camp young men masquerading as adults, a land of certainty, solidity, security, standing alone against the perfidious Germans, the capitulating Belgians and the weak and hopeless Frenchies; a land where the little women stayed in the shadows, where men had watch-chains and pin-striped suits and all dressed like Nigel Farage and drank whiskey from crystal tumblers served by footmen and smoked on the tube and made ringing speeches in the House; a land where there was no Gina Miller to darken the doors of justice and try and cheat us out of voting to cut our own throats.

Darkest Hour portrays the few weeks in May 1940 when the great appeaser Chamberlain (played by Ronald Pickup) was forced to resign and a coalition was formed with Churchill at the helm. The film is book-ended with his two speeches – it starts with him offering the House nothing but tears, toil and sweat and ends with his vow to fight them on the beaches and never surrender. And in between, we see him developing a relationship with the King (George Vl played by Ben Mendelsohn) who sounds like Jonathan Ross, all ‘thwones’ and ‘must twy harder,’ being nice to Clemmy, impressing a young typist (Lily James), sparring with Lord Halifax who is desperate to sue for peace and then blithely sending 4000 men to their deaths in Calais in order to buy time to save the nation.

There are two main characters in the film – Churchill (of course) and a young typist – Miss Layton – played by Lily James. The typists in these sorts of films are always portrayed in the same way: they’re impossibly beautiful and gloriously slim, they start out nervous and make mistakes and want to run away until the Great Man nurtures them and then they blossom. There’s always a moment when the Great Man thaws and takes them under their wing and shares secrets, as here when Churchill takes her into the (forbidden) map-room and shows her all the little pins denoting the German forces encircling our brave boys. And there’s always a little tear as here when Lily mouths the words of the no surrender speech which she has just typed for the gruff (but nice really) Mr Churchill. Just once, just once mind you, why can’t the typist look like Mrs Doubtfire with a face like a bag of spanners and a body that’s lived-in instead of lain-on and just get on with being a woman with a job of work instead of a simpering, blossoming young girl?

Kristin Scott-Thomas (Clemmy) is still beautiful, although looking increasingly brittle and cadaverous; her cut-glass posh accent is still the best. She does her best with little to do. There is an odd moment where she berates Churchill for spending too much money and says they can’t pay their bills any more but this story arc never goes anywhere and we don’t find out if they ever make any money. (As Churchill – I always thought rather oddly – subsequently received the Nobel prize for literature, one assumes they didn’t stay broke for too long).

There are bits that may be factually correct but certainly didn’t ring true. Did Churchill really ride the underground for the first time on his way to the House to give his ‘no surrender’ speech? Did he really get the idea of ‘no surrender’ by talking to housewives, working class men and spunky children and quoting Shakespeare with an African immigrant in a pork pie hat? And in the days before social media and television would everyone really have recognised him immediately? Did the underground really take quite that long to travel one stop? Did Churchill really not know the meaning of the two-fingered gesture? His knowledge of English history would surely have seen him fully aware of its origins with the bowmen of Crecy.

Much of the film takes place in the Cabinet War Rooms, although as London was not being bombed in May 1940 it is hard to see why this was necessary. (And Clemmy remains upstairs in 10 Downing Street, presumably happy to be blown to bits as long as Winnie survives). It did give the film-makers the chance to show the claustrophobic conditions underground, the cramped meeting rooms, the dingy map room, typing pool, the toilet just for Churchill’s own use – all familiar to those who have paid the price of admission (and now no doubt will do again) to see this outpost of the Imperial War Museum.

Gary Oldman as Churchill has been rightly lauded and his performance is a tour-de-force. There were times when he seemed to walk a bit too easily and too quickly portraying a man of 65 who was very over-weight and smoked incessantly. But still, he was appropriately jowly with thinning hair and made a good stab at the accent, although the perpetual cigar often appeared unlit.

Director Joe Wright also made Atonement, a much more profound and layered work about class and war. Parts of that were about the retreat to Dunkirk and it sometimes seemed as if Wright had some film left over which he used to show the defence of Calais.

Darkest Hour is an enjoyable movie and a decent film. However, I can’t see any great reason for anyone much under 50 to see it – unless they’re ardent Brexiters, of course – last year’s Dunkirk covered much the same ground and although that was a pretty terrible Brexit film, there are some decent action sequences and Mark Rylance and Harry Styles are in it.