The story
Rhyming slang: tod = Tod Sloan = own, a reference to the US jockey Tod Sloan. Various theories suggest a possible additional connection between Tod Sloan and solitude: that he died alone in impoverished circumstances, that he pursued his career "alone" on his own terms, or that he won races from the front, riding alone.
Etymology from Wiktionary, CC BY-SA 4.0.