Bela Lugosi made a lot of schlocky films during his career. While DARK EYES OF London is definitely a low budget film, thanks to decent writing and a very creepy style it manages to entertain even after almost 70 years.
Bela plays a totally amoral criminal who runs an insurance company. He insures people and makes himself the beneficiary after making these people loans. But instead of waiting to collect the money, he drowns them and throws their body in the Thames. While an interesting scheme, he oddly does it repeatedly--naturally arousing the suspicions of the police.
In addition to being an insurance man, Lugosi also is a benefactor to a home for indigent blind men. However, this act of kindness is a front, as this home is where Bela commits his murders with the help of a truly horrifying looking blind assistant. Near the very end, you actually get to see him kill one of his innocent victims and toss him in the river in a very graphic way--hence deservedly earning its special horror rating in the UK.
The film earns some points for an unusual plot and its graphic scenes--it really is a pretty scary film for 1940. However, there are a few lulls, some overacting by the idiot playing the cop from Chicago and the irrationality of Lugosi committing so many murders yet hoping to get away with it when he's the only rational suspect. By the way, speaking of the Chicago cop, do all Brits see us Americans as THAT brash and annoying?! I sure hope not! You also wonder why they even bothered including this character, as he was rather distracting and unnecessary.