Harry Jones was the secretary of the Communist Party of Great Britain in Reading.

On the outbreak of the Spanish Civil War Jones became very involved in the campaign to support the Popular Front government against the Nationalists led by General Francisco Franco.

In August 1936 it was decided to form a Spanish Medical Aid Committee. In his autobiography, All My Sins Remembered (1964), Peter Spencer, 2nd Viscount Churchill, explained what happened: "A group of us - three well-known medical men, a famous scientist, several trade unionists, and one communist - formed a committee for the purpose of collecting money for medical supplies to be sent to the Spanish Government forces."Jones helped to persuade Roy Poole, John Boulting, Rosamund Powell, Thora Silverthorne and Reginald Saxton to join this group.

Jones also played a role in encouraging Josh Francis, William Ball, Frank Hillsley, George Middleton and Jimmy Moon to join the International Brigades.