Brian Leonard Clementson joined British Railways as an Engineering Apprentice in 1960 and undertook a Sandwich Course. He undertook an extensive variety of train engineering roles from the 1960s to the 1980s. He worked as Director Fleet for Trainload Freight and was appointed as Director Fleet for InterCity in 1992. He joined Porterbrook as Engineering Director in 1994, before moving to becoming the Managing Director of Railtest in 1995.