Steel was an MP for Roxburghshire, Selkirkshire & Peeblesshire 1965-74, Roxburgh, Selkirk and Peebles 1974-83, and Tweeddale, Ettrick & Lauderdale 1983-97. He served as leader of the Liberal Party from 1976 to 1988, and as Joint Leader of the merged Liberal and Social Democrats in 1988. He was presiding officer of the Scottish Parliament from 1999 until 2003.
- Tackling Terrorism All-Party Parliamentary Group - Vice chair 
- All-Party Parliamentary China Group - Deputy chair