Confusing but exceptionally well executed.

Rating: 7/10 (1 August 2017)

For anyone who does not know what happened in the early years of WWII this could well come across as an exceptionally well-crafted fictional period piece. There was a short text preamble that said British and French troops had been forced back to the coast by the enemy. No mention of when or why they were there, or even who the enemy were.
The film certainly has bouts of dramatic tension, and there are the expected triumphs and tragedies. There being such little dialogue has created a visual and aural masterpiece. I wonder if a cut will be made that has all the dialogue removed just leaving the soundtrack and sound effects.
There are 3 narrative threads: these are sometimes sequential, at other times they overlap and sometimes they jump back and forth in the time-line - quite confusing.
There are some marvellous flying sequences and I particularly appreciated (to my layman's eye) the minimalist use of CGI.
With the almost faultless attention to period detail that sets this film apart from many others set in WWII it was ruined by a glaring anachronism near the end when railway carriages of 1980s/90s vintage were used, complete with Formica tables and ghastly British Rail upholstery, and not a compartment to be seen anywhere, which I believe was the norm in 1940s.
I had expected more from this film.