His playing career began with Marlow, where he was spotted playing in the Athenian League at the age of 16, and after spending time with Chelsea and Derby County, he signed a pro deal with Watford.

It was at Vicarage Road that Markham was converted into a centre-half - previously he had been a free-scoring centre-forward.

Leo then moved into non-league football with Wimbledon and when they gained entry into the league he decided to call it a day, at the time saying he fulfilled his ambition to play pro football, but it wasn't all it was cracked up to be.