I've seen 'Dunkirk' twice now.

The first time was at my local Cineworld. I then saw it on an IMAX screen in Milton Keynes.

I won't review the film because I'm no good at reviews and there are a million out there already. (See Rotten Tomatoes.)

But I do recommend it.

The first time I went with my son. We both enjoyed it but I made the rookie mistake of reading many of the mostly superlative reviews in advance and it's hard for anything to live up to that level of hype.

The one aspect of the film that slightly disappointed us was the scale. In reality there were almost 400,000 soldiers awaiting evacuation from Dunkirk.

Over 900 vessels were involved in Operation Dynamo including over 700 'little ships', with 15 Spitfire squadrons providing air cover.

'Dunkirk', a £150m Hollywood movie, doesn't even hint at this. What we see is a few thousand extras on a largely deserted beach, one or two warships, a handful of private boats and three Spitfires.

Ironically 'Their Finest', a small budget movie about the making of a wartime propaganda film about Dunkirk, addressed this logistical issue.

Released earlier this year there's an amusing scene where the tricks of a pre-CGI age are demonstrated in all their glory.

What appears to be a beach heaving with soldiers is actually a piece of glass placed in front of the camera. It was nevertheless surprisingly effective and the audience laughed when the subterfuge was revealed.

'Dunkirk' director Christopher Nolan is having none of that. CGI too is kept to a minimum.

What we have instead is a series of relatively intimate vignettes with the emphasis on verisimilitude, and credit to him for that.

The soldiers on the beach are not computer-generated, they are real people.

The small flotilla of 'little ships' is mostly genuine too - 12 or 13 actually took part in the Dunkirk retreat.

The Spitfires are authentic working aircraft.

Compare this to the bombastic, CGI-driven nature of every other Hollywood blockbuster.

Prior to the Cineworld screening of 'Dunkirk' we sat through trailers for several forthcoming films.

One was yet another Marvel Comic movie. Another was a 'Game of Thrones' style fantasy.

A third was an unbelievable and ludicrously over the top disaster movie built on the premise that one day we'll be able to control the weather from space but what happens if it all goes horribly wrong.

I assure you that, regardless of one or two minor flaws, 'Dunkirk' is a masterpiece by comparison and we should be grateful Nolan has made a film that can be watched by adults as well as teenagers.

In short, warmly recommended. Disregard the hype (difficult I know) and you'll enjoy it even more.

Most important, watch it at an IMAX cinema. The difference is significant.

The picture was clearer, the surround sound far more intense. There were moments when the seats positively trembled in sync with the permanently throbbing soundtrack and the inevitable explosions.

Oddly the paucity of soldiers, aircraft and ships seemed to matter less on the larger screen.

I think it's because the experience is so much more immersive. Rather than observing the protagonists you feel you're with them in their battle for survival.

Best of all are the airborne dogfights that really come to life on the bigger screen.

My wife, who does not as a rule enjoy war movies, preferring a quiet matinee-style film on a modest screen at the Arts Picturehouse in Cambridge, said it was one of the best films she'd ever seen.

Take it from me, that's some accolade.

PS. Interesting to note, from US reviews of the film, how little is known about the evacuation of Dunkirk in America.

The same is true, I'm sure, of us and important moments in US history.

A better appreciation of the history of our friends and foes is fundamental, in my view, to successful foreign relations.

The Foreign Office no doubt understands this which is why so many ambassadors and civil servants are accused of 'going native'.

But that's another story for another day.

PPS. Have IMAX screens got smaller? Prior to last week I'd only been to two IMAX cinemas, one in London, the other in Glasgow, the last time almost ten years ago.

The Milton Keynes screen was large but it wasn't MASSIVE in the way the London and Glasgow screens were so I may have to watch 'Dunkirk' for a third time on an even bigger screen.