See the "Bless 'em All!" thread for complete, complicated details.

A summary:

Fred Godfrey was a well-known English composer. Evidently, while in uniform in 1916, he casually lit the flame of "Bless 'em All!" by setting original (lost and, they say, unprintably satirical) lyrics to a variant of this melody. Not too surprising, since Godfrey's song was intended solely for his messmates in the Royal Naval Air Service.

The new, popular version, with presumably brand-new lyrics, appeared in 1941, without acknowledgement to Godfrey. But the publishers soon acknowledged his name. Just what evidence he showed them appears to be lost.

Beyond that, the pre-1941 history of "Bless 'em All!" remains entirely obscure. But the melody's essential identity to Robinson's music-hall song of the 1890s is unmistakable.