Between 1950 and 1954 Sprague worked in a Carlisle mining company design office – doubling as a cartoonist for the local Conservative and Liberal newspapers. Then came a move to London as the "Daily Worker"'s publicity manager, which also had him working as a journalist and cartoonist. Devastated by the Soviet invasion of Hungary in 1956, in 1959 Sprague left to set up, with Ray Barnard, the publicity company, Mountain &amp; Molehill (M&amp;M). Yet he continued producing cartoons for the "Worker", and its successor the "Morning Star", into the 21st century.