He grew up to become the Chief Whip of the Conservative Party in late 1963. In order to re-establish the Light's weakened hold on Earth, he plotted to destroy the new United States of America and USSR. He and his allies, including Sir Francis White, ensured Alec Douglas-Home became Prime Minister as a fall guy, then — while masquerading as "Martin Regan" — organised several assassinations through Disarmament Now to get White as Defence Secretary and himself as Deputy Prime Minister. As the Chief Whip was by tradition meant to be out of the public eye, nobody connected him to Regan.
Devere and the Light rigged for the Starfire missile test to wipe out the United States and for the Soviet Union, its arsenal disabled by secret code, to be blamed and hit with a British "retaliatory strike", but his plan was thwarted by the Seventh Doctor and the Intrusion Countermeasures Group. He was in semi-psychic communication with most of the Light's other agents when the Doctor dropped the Starfire missile on him. (AUDIO: 1963: The Assassination Games)