An article "How altered aspect ratios on TV ruin feature films" by Nick Gillis on |Den of Geek here:
www.denofgeek.com/movies/1028066/how_altered_aspect_ratios_on_tv_ruin_feature_films.html"British television despises films, it seems. Every day, UK channels alter the very shape of the movies we watch, otherwise known as their aspect ratio.
Old films that are almost square will often have the top and bottom cut off to fit the shape of modern 16:9 screens – The Ladykillers, screened this month, is but one example. Big films shot in Panavision (Master And Commander, for example) will frequently have the left and right hand portions of the image cropped for the same purpose.
...This isn’t just geeky nitpicking, either. Your first exposure to a director’s work is likely to be on television, and in the case of Ken Russell, a poorly presented version of one of his films may discourage viewers from seeking out other examples of his work. This is particularly true of his 1967 movie, Billion Dollar Brain, which I’ll come back to later.
How much worse, then, is the offence of changing the aspect ratio of a movie? Two films of Len Deighton’s books illustrate the barbarity of fitting everything to 16:9. The Ipcress File is famous for its angles and split screen work – that is, unless it’s aired by the BBC.
Billion Dollar Brain has often been regarded as inferior to The Ipcress File. That’s because most people have seen it on TV. Ken Russell had a gift for composition, filling his wide screen with memorable images: the helmets of soldiers as they wait to invade Russia, or Helsinki in winter, for instance..."
I've never liked Billion Dollar Brain but someone else recommended it to me as well, so maybe I need to re-watch.