I take the liberty of quoting part of an IMDb review by dbborroughs, because it describes the plot so accurately and succinctly:"It begins with complex web of events: Two thugs are waiting to meet up with a third in a seaside hotel. They find their friend dead on the beach and promptly rob him of all his goods. An "accident" at a mine is blamed on the manager who is dismissed. The mine owner, who is being blackmailed and is in fear for his life, sends a message to super sleuth Sexton Blake to come and investigate. A mysterious voice gives instructions to a henchmen from a hiding place deep in a sea cave...
From there is spins out into a mostly exciting tale of intrigue and espionage. This plays out like a Hollywood programmer but on steroids, with big destructive fights, twists that are twists and a go for it attitude that can't be beat."
Many thanks for the use of this description.
Sexton Blake, of Baker Street, is as you might have guessed, is a modern Sherlock Holmes type - here well-played by David Farrar. He has friends in the underworld he can tap for info as well as friends in high places, who listen to his advice and act on it.
This movie starts as a complex bunch of murder mysteries and escalates into something much greater. Once it gets going, it is easier to follow that it was at the start - and plays to a great concluding scene. All the actors do a fine job. Worth watching.

If you ever call me a fool again I shall kill you..and it shall be bloodless..
Now how much more formal can you get when threatening someone's life short of putting it on an engraved invitation? LOL

I like David Farrar as Sexton Blake much better than George Curzon, who played the part in earlier times.
I have this title and "Meet Sexton Blake" on VHS and watch them once in a while. Lots of background scenery of London.
Danny Green's most famous part was in "The Ladykillers" with Alec Guiness.

David Farrar played a bit part in "The Hooded Terror", another Sexton Blake showing here. He went on to star for Powell & Pressburger.

3 Days ago I didn´t know anything about this man, now I have watched 2 movies here at IA (the other one is "Sexton Blake and the Hooded Terror), both I do recommend.

This one has a more complicated plot than the other because there are many different villains working on their own purpose. Maybe in the end not every loose end of the script gets tied together but it is a fast paced action story which keeps your interest and the acting is adequate.

You can see Ferdi Mayne (I absolutely adore him in "The Fearless Vampire Killers" by Polanski) in a small part as minor villain trying to keep his brainless partner under control. He does a good job.

Look out for Carl. He is played by Danny Green. Not important to mention him for his work in this film. I do not even remember if he has any lines to say. His job is beating up people, not talking. But later he will be a wonderful Karim, the leader of a mutiny against Sinbad the sailor in "Sinbads 7th Voyage" from 1958.