At the outbreak of the Great War, Millar joined up with The Artists’ Rifles, serving at The Front for the entire war. He was one of the first victims of mustard gas at Vimy Ridge and his injuries would blight him throughout his life.
After the War, aged 22, he studied briefly at The Slade before returning to his career in advertising, supplementing his wages by producing sports cartoons for The Daily Chronicle and illustration work for The Sphere. In the Spring of 1921, Millar answered an advertisement in the Daily Sketch announcing an open competition for a feature cartoon to rival the success of their tabloid competitor, The Daily Mirror.
Millar drew a characterization of a young man about to marry and ‘Reggie Breaks it Gently’ appeared as the first strip cartoon in the Sketch on 20 May 1921.
The strip was an immediate success however the paterfamilias character of ‘Pop’ soon superceded Reggie as the eponymous title-bearer for the strip.
POP became hugely successful on both sides of the Atlantic and across the Commonwealth. At the outbreak of World War II, Millar wished to end the strip but was persuaded that ‘Pop’ was necessary for the War Effort, to boost morale. It may even have been that King George VI and Churchill were both identified as fans of the strip.
The strip cartoon ran daily until 1949 after which Millar Watt concentrated on illustration and advertising work. The Sketch were loathe to lose such a popular feature and a staff artist, Gordon Hogg, continued the strip until the tabloid was incorporated into the Daily Mail in 1971.
On May 20th, 1946 The Daily Sketch published a silver anniversary edition to commemorate 25 years of the ‘Pop’ cartoon, among many esteemed contributors from the world of art and cartooning, among them Millar’s friend Sir Alfred Munnings, who wrote,“I have the greatest admiration for Millar Watt both as an artist and a man. I have known him for years. Some of my happiest days have been out sketching with him in Suffolk. He lived in the same village in Essex and we used to go out together in his car to sketch landscapes. And now his Dailly Sketch character ‘Pop’ is 25 years old! How has he kept it up! I congratulate him on this achievement and keeping always a marvellous and clean level throughout”
Twenty five POP albums were produced from Millar’s drawing of the strip. Each Christmas Millar would have the entire stock of originals sent down by train to his home and he would lay them out in two long aisles on his studio floor, then choose the strips that would go into publication. He gave each album a comic title and artwork for the cover. He would often design the entire publication, crafting a cartoon for a frontispiece and on occasion, and end piece too. Often, the advertisers in the album would commission Millar to feature POP in the artwork for their own adverts.