[1] Born in Greenock on the River Clyde, Scotland, the son of James H. Watt, an engineer, and his wife Henrietta.
He was apprenticed to an advertising agency whilst attending evening classes at the Westminster School of Art.
His apprenticeship was interrupted in 1915 by World War I during which Watt served with the Artists' Rifles and the Essex Regiment.
In 1921 he created a comic strip for the Daily Sketch entitled Reggie Breaks It Gently but the lead character was soon to become known as Pop, a rotund businessman usually to be found in a bowler hat, waistcoat, striped trousers and spats.
Watt continued to draw Pop until 1949, leaving to concentrate on lucrative advertising and illustration work.