Best known as the creator of the character 'Pop', who was featured in a strip cartoon in The Daily Sketch (and subsequently The Daily Graphic) for over 25 years from 1921, he nevertheless took his art seriously and his paintings were well regarded.

Born in Gourock, Clyde, he was educated at Ilford, Essex and at Cass Art Institute before joining the advertising agency Mather and Crowther. In WWI he enlisted in the Army and served as a lieutenant at Vimy Ridge, where he was gassed. Afterwards he continued his art studies at St Martin's and at the Slade in the evenings.

In 1923 he married Amy Maulby WATT nee Biggs and they settled at Dedham, Essex, where he became friendly with Norman GARSTIN. One of his 'Pop' cartoons was included in the STISA 1936 tour, but he restricted his exhibits to landscapes and still lifes. He was elected onto the STISA Committee in 1936 and again in 1937, 40, 41 and 43, and it was he who in 1945 put forward the proposition that the Mariners' Chapel should become the new Gallery for the Society.

Watt had wanted to retire 'Pop' in the late 1930s so that he could concentrate on fine art but the continuance of the comic strip was considered of vital importance to national morale - King George and Winston Churchill were fans - and he was persuaded to carry on. 'Pop' accordingly, like Watt himself, joined the Home Guard. By 1945 over 7,000 cartoons had been published.

After the war he and his wife moved to Chelsea and after her death in 1956 he moved to Lavenham, continuing in commercial and fine art. His advertising work included the famous 'More Hops in Ben Truman' campaign of the 1960s and 70s, and his illustrations featured in magazines such as Reader's Digest, Look and Learn, Everybody's and the Princess comic.