Hired by Richard Burton to write a film script about the famous "Great Train Robbery" of 1963, in which approximately £2,500,000 in cash was stolen from a mail-train. Anthony Mann was suggested as director, with Burton starring, but the idea fell through. A film inspired by this crime did appear in 1967 ("Robbery", directed by Peter Yates), and did have a Welsh leading man (Stanley Baker), but Thomas's script was not used.