What was the real name of Captain Scarlet in the British TV series of the same name?

"Captain Scarlet and the Mysterons", often shortened to "Captain Scarlet", is a British science-fiction television series created by Gerry and Sylvia Anderson and filmed by their production company Century 21 Productions. Running to thirty-two 25-minute episodes, it was first broadcast on ITV regional franchises between 1967 and 1968 and has since been transmitted in more than 40 other countries, including the United States, Australia, New Zealand and Japan. It is one of several Anderson series that were filmed using a form of electronic marionette puppetry dubbed "Supermarionation" combined with scale model special effects sequences.

Captain Scarlet was the code name of Paul Metcalfe whose nationality was British. Francis Matthews supplied the voice of Captain Scarlet. Gerry Anderson went to great lengths to cast him because he was impressed by an imitation of Cary Grant that Matthews had once used in a radio programme, and indeed the actor based Scarlet's tones on Cary Grant's Mid-Atlantic accent.