[2] Born in Hampton Wick in 1888,[3] his parents were George Marsh and his wife Laura.
From 31 August 1915,[2] Gerahty served in the Royal Navy Volunteer Reserve, with the rank of lieutenant and in 1919 he was mentioned in despatches for his services in action against enemy submarines off Gibraltar.
[9] He was author of The Road to Madrid about the rise of General Franco and the Spanish Civil War.
[10][11] The Daily Mail was staunchly pro-Franco and Gerahty was a key apologist for the Nationalists in their attempt to refute the bombing of Guernica.
He also published documents, later shown to be forgeries, alleging that radical insurrections were being planned at the time that the army revolted.