What was the code name for John Steed's boss on the TV show "The Avengers"?

On the 1960s British espionage TV series "The Avengers", the code name for John Steed's boss was 'Mother'. In this series, the government official who gave Steed his orders was a man depicted in a wheelchair. He was only called Mother and was introduced in the episode "The Forget-Me-Knot". The role was played by Patrick Newell.

Mother's headquarters during the series would shift from place to place, including one episode where his complete office was on the top level of a double-decker bus. This is a feature that several James Bond films of the 1970s would make use of as a similar gimmick where Bond could hold briefings.

Also, later in the series, another character was added as a regular. She was Mother's mute Amazonian assistant, Rhonda. She was played by uncredited actress Rhonda Parker. Additionally, there was one appearance by an agency official code-named "Father". She was a blind older woman played by Iris Russell.