Heppell was elected as a councillor to Nottinghamshire County Council in 1981, serving as the deputy leader for three years from 1989, stepping down from the council in 1993. He was elected to the House of Commons at the 1992 general election for Nottingham East by defeating the sitting Conservative MP Michael Knowles by 7,680 votes and remained the MP there until 2010. He made his maiden speech on 11 May 1992, in which he recalled that it was in his constituency at Sneinton that the founder of the Salvation Army William Booth launched his crusade against poverty in the early 19th century.