Considering the number of times 'Albert R. N.' is rolled out on UK terrestrial channels, it receives very little attention on IMDB. The movie is based on a play that is based on an event that actually occurred in WWII, when official war artist John Worsley was a POW and created just such a dummy to fool German POW headcounts.
It worked for four days, apparently, while in the movie Albert serves for months.
This movie is best watched as an example of UK war propaganda (8 years) after the event. Any resemblance of characters or plot to reality is nonexistent. Anton Diffring is as usual a convincing SS officer, except his uniform appears to be home-made - and they forgot the death's head on his cap. Most of the rest of the cast appear to have discovered a secret cache of doughnuts, as if in 1953 people didn't appear to understand the link between POW rations and weight loss. They did, but the news hadn't reached Nettlewood Studios.
'Break To Freedom' ('Albert R. N' in the UK, a much better title) is worth watching as a window into old-fashioned war drama; it's well structured and not that boring. It's just unrealistic to the point of surrealism. Jack Warner doesn't so much phone it in, he texts it.
The dummy, though. Eerily like Dickie Attenborough, who appeared in many a film of this genre.