Which British TV character lived at 5 Westminster Mews, London?

Major The Hon. John Wickham Gascoyne Beresford Steed usually known as John Steed, is a fictional character and the central protagonist on the popular 1960s British spy series "The Avengers" and its 1970s sequel "The New Avengers", played by Patrick Macnee in both.

Steed is a secret agent working for an unnamed branch of British intelligence. He was teamed with a variety of partners, including Dr. David Keel (1961), Dr. Martin King (1962), Venus Smith (1962–1963), Cathy Gale (1962–1964), Emma Peel (1965–1968), Tara King (1968–1969), Lady Diana Forbes-Blakeney (1969), Purdey, and Mike Gambit (both 1976–1977).

He maintained a modest mews flat in London during the 1960s (first at 5 Westminster Mews, later at 3 Stable Mews) and drove a variety of elaborate, old-fashioned cars, including a Rolls Royce and several different models of Bentley, one of which he calls Fido.