God bless scientists. Frequently dismissed by a philistine public as geeky, nerdy and socially inept, they nevertheless push daily at the very boundaries of human knowledge, often without tea breaks. However, on occasion their breakthroughs have owed more to luck than scientific rigour; their successes have hung on a single decision made years beforehand; and the one brilliant discovery that has made their name and brought about a seismic change to society has occurred while they were pursuing something else altogether.