How did the British solve the Morse code?

Answer 1

I think you must be confused, Morse Code is a method of transmitting text information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment,

a in:-

...---... ( where ...="S" and --- ="O" so the message reads "SOS")

As the code was invented and published, there was noting to "solve".

I think you must be thinking about the German "Enigma" code. If so please re ask you question using that as the topic.