By 1963, both he and Devere were Members of Parliament and Devere was Chief Whip, but the Light was losing influence on Earth due to the decline of Britain and rise of new superpowers. White was part of a plan to use Vale's Starfire missiles to destroy both the US and USSR.
As part of the plan, White helped make Alec Douglas-Home made party leader: “a fool to take the fall”. Another boy from school, Martin Regan, was abducted, murdered, and set up as a fake leader of a terrorist group (mainly because he'd annoyed them). Later, Stephen Mulryne was assassinated (White found it funny) so White could be made the new Defence Secretary. When the Seventh Doctor, masquerading as an MP named John Rutherford, raised questions about the assassinations, White threatened him and was threatened in turn. When Allison Williams learned about part of the plot, she warned him about it thinking he was trustworthy.
White was prepared to die making sure the Starfire plan worked, and killed the hapless Vale for trying to interfere. However, Ian Gilmore was able to kill him and allow the Doctor to abort the Starfires. (AUDIO: 1963: The Assassination Games)