Bernard Harold Ian Halley Stewart, Baron Stewartby, was a British Conservative Party politician and numismatist. He was the Member of Parliament for Hitchin from February 1974 to 1983, and for North Hertfordshire from 1983 to 1992. He sat in the House of Lords from 1992 to 2015.

Hitchin was a parliamentary constituency in Hertfordshire which returned one Member of Parliament (MP) to the House of Commons of the Parliament of the United Kingdom from 1885 until it was abolished for the 1983 general election.