Mills was the dominant British cyclist of his generation. In his career, he established 19 separate records (surpassed only by Monty Holbein who had 32). He completed the Land's End to John O'Groats route successfully six times - once by Ordinary, twice on a safety, twice on a tricycle, and once on a tandem (with T.A. Edge). His triumph at Bordeaux-Paris probably remains the greatest single British cycling triumph on the continent.