Lawrence Theodore Thomas Steel, known as Theo Steel, was born in 1951. He went on a British Rail short works course in 1966 and worked in the British Rail: Southern Region planning office during the summers of 1967 to 1969, before becoming a Planning and Marketing Graduate Trainee in 1970. He served as Secretary for British Rail Passenger Committee and worked in Travellers Fare Train Catering between 1976 and 1978. Continuing his work in railway catering in 1978 he became the East Coast Train Catering Manager until 1982. He was then appointed as Passenger Manager, Liverpool Street Division in 1982 and worked as London and South East Manager. He became Assistant General Manager, British Rail: Eastern Region, before moving to British Rail: Western Region in 1987 and worked as Corporate Affairs Director at Swindon. He was involved in the Channel Tunnel Rail Link consultation in 1988. He was appointed Director of Regional Railways South Wales and West until 1995.

Post-privatisation, he has worked as Business Development Director for London and Continental Railways between 1996 and 1998 and was also involved with the European Night Services Joint Venture. From 1998 he served as Commercial and Deputy Managing Director for First Great Eastern, staying in this role until 2004. He then became Project Director for National Express Anglia until 2010.He has also been an Advisor to Railway Heritage Trust and Chair and Governor of Rail Heritage Awards Judges, both roles are thought to have commenced in 2000.

Outside of the railway industry, Theo Steel has sat as Chair of Southend Council Business Partnership between 2000 and 2006 as well as Chair of the Essex Development Agency, serving in this capacity from 2004 to 2009. Additionally, between 2004-2010 he also held the Chair of Regeneration Southend.