The true origins of the plot for the Great Train Robbery will never be know for sure, there are too many twists and turns that its difficult to see what is fact and what is legend. The popular legend has it that a bent solicitors clerk (Brian Field) contacted a couple of thieves he knew (Buster Edwards and Gordon Goody) to tell them he knew a man with knowledge of the railways and how large amounts of cash were moved around the country. They all met - Finsbury Park was at least one venue - and the man Brian introduced came to be known as The Ulsterman. But was the information The Ulsterman gave the robbers accurate, was some of it available elsewhere that they could have easily tapped into? Was some of the story or legend of The Ulsterman created to 'spice up' an old story when the robbers came out of prison. Was The Ulsterman simply a myth? This is the third in a series of short pieces (about a quarter book length) looking at the Great Train Robbery, and it examines the role of The Ulsterman. I consider what the robbers have told us and how some of the facts were questionable, but not all commentators have considered the information given by the General Post Office and British Rail staff. This series of essays is to stimulate discussion. My first essay was knocked because I called the Director of Public Prosecutions by their latter day title of the Crown Prosecution Service: for some reason the review was entitled Unsubstantiated Ravings! A follow-up laid criticism for not putting in an apostrophe! If these are the only faults, then it does suggest the overall content of my discussions might have some merit and therefore something to offer the reconsideration of history in Britain in the 1960's.