He began his "professional" career as an artist while held as a Japanese POW during World War II, where he managed to produce hundreds of drawings showing the horrific conditions in the camp. He was a prolific creator, producing books, cartoons, adverts and films, and was a great influence on many other artists. There is an utterly charming interview with him here (youtube) and some more pictures here (drinking his daily champagne, what he called his "engine oil"). Personally I love him most for the glorious Molesworth - the 1950s prep-school boy aka the "goriller of 3B" and "curse of st custard's which is the skool i am at" (and who these days can be found on twitter) whose particular brand of appalling spelling and slang still resonates deeply with many readers: the normally straight-laced Economist newspaper gave Searle this beautiful and very fitting obituary.