Inferno universe

In one parallel universe, Great Britain was a Republic governed by a fascist regime.

19th century
The Confederates won the American Civil War.

20th century
Joseph Stalin was, in this world, a Menshevik. Prior to 1943, the British royal family had been executed for undisclosed reasons at some point prior to 1943. The Japanese successfully built their Asian Co-Prosperity Sphere. The Second World War never happened since Europe was divided into allied British and Russian spheres of influence to intimidate Hitler into backing down from his sabre-rattling.

This world was effectively ruled by the Conclave, a parallel of the United Nations Security Council. The Conclave were based at Copernicus moon base to protect the delegates against the possibility of attack and to intimidate subversive groups and enemy nations. The reasoning being that since the Moon could be seen from all parts of the civilised world it would serve as a reminder that the Conclave was watching.

There was no direct parallel of UNIT, instead national military organisations undertook its responsibilities. In Britain the state security militia was the Republican Security Forces. Many of it's members were the parallels of British UNIT members Alistair Gordon Lethbridge-Stewart, Elizabeth Shaw and John Benton. (DW: Inferno) Shortly after the the Doctor's unplanned arrival in this universe, an accident at Stahlmann's project devastated the entire surface of the planet within thirty-nine hours. The only survivors were those in bunkers, space stations or on the Moon. (PDA: The Face of the Enemy)

At the time of the devastation, the Doctor's parallel self was the leader of Great Britain. He was killed when the fallout from the disaster at Eastchester destroyed London. (NA: Timewyrm: Revelation)