The Leader

In a parallel universe, the Leader was the President of the Republic of Great Britain and was believed to be an alternate version of the third incarnation of the Time Lord known as the Doctor. (PROSE: Timewyrn: Revelation)

Biography
This universe's version of the Second Doctor selected one of the bodies offered to him by the Time Lords after his trial. (PROSE: Timewyrm: Revelation, TV: The War Games) Like his counterpart, this version of the Doctor was banished to Earth in the 20th century.

His TARDIS materialised in 1930s England, as opposed to the 1970s where his counterpart was sent, where he became an ally of Oswald Mosley. The two were regulars at the Revolutionary Arms pub in Westminster, and a photo from the era showed the Doctor drawing a beer for one of his colleagues — in public, he projected a kind avuncular personality, covering a cold and ruthless core.

After Mosley was assassinated while giving a speech at the Free Trade Hall in Manchester in 1936, the Doctor became the new leader of the revolutionary movement helping to craft Mosley's legacy as a martyr of the British people, and subsequently claimed Mosley's title of "Leader" for himself. (PROSE: I, Alastair)

In 1943, the revolution finally arrived, the old democratic regime collapsed and numerous executions were carried out on the Leader's orders, ostensibly those who had conspired to assassinate Mosley, including, among others, the British Royal Family. (PROSE: I, Alastair, TV: Inferno)

The Leader's bodyguards and physicians were aware of his great age and alien biology, but this was generally dismissed as fanaticism by most Party members. He could no longer regenerate, as the Time Lords had taken this ability from him. (PROSE: I, Alastair)

By 1968, the Leader had become irritable and paranoid, sacking members of his Cabinet for perceived slights and failings, demoting Arthur Fless, Director of Information, to a remote colonial posting in West Africa for failing to locate an illegal radio transmitter interrupting RBC broadcasts with anti-Party propaganda in the London area. His health had severely declined and he was visibly elderly as his age caught up with him; he spent two months at his seaside retreat in Bognor Regis to convalesce from a condition afflicting his hearts but suffered a stroke soon after, confining him to a wheelchair. The Cabinet had started jockeying for power on assumption the Leader would not survive much longer, but he still retained his intelligence and cunning. (PROSE: I, Alastair)

The Leader was killed in 1968 when Gordon Lethbridge-Stewart opportunistically used his wheelchair as a battering ram during an alien attack on Downing Street. After his death, the Leader's popularity with the public remained high and years later portraits and posters of him remained omnipresent to cement the legitimacy of President Lethbridge-Stewart's regime. (PROSE: Night of the Intelligence, I, Alastair)

However, according to another account, the Leader perished in the 1970s when a secret British science project conducted at Eastchester, which involved drilling beneath Earth's crust to gain access to pockets of a potential new energy source, went terribly wrong — not only releasing an unidentifiable green, viscous substance that transformed humans into savage werewolf-like creatures on contact, but also enough energy to devastate the planet beyond recovery. (PROSE: The Face of the Enemy)

During a conversation with the Seventh Doctor, the Third Doctor recalled the face on the poster in the hut at the Inferno Project, and described its similarity to the one offered to him by the Time Lords, concluding the Leader was an alternative incarnation of his. (PROSE: Timewyrm: Revelation, TV: The War Games)

Behind the scenes

 *  Revelation is not specific about which of the faces offered by the Time Lords in The War Games was chosen. It is likely the third one, rejected by the Second Doctor for being "too thin".
 * A black-and-white photograph of the BBC special effects designer Jack Kine were used to depict the Leader on the UNITY IS STRENGTH poster in the Technical Store, the Doctor's hut on the regular Earth timeline; and the framed picture on the wall of Brigade Leader Lethbridge-Stewart's office in Inferno. However, the Leader never appears on-screen in person and there is no on-screen evidence to suggest that the Doctor and the Leader had any connection; this connection was made only in the novels.
 * Robert Mammone, interviewed in 2021, noted that the Leader's paranoia and tendency to play cabinet members off against each other are based on Josef Stalin. He also admitted that when writing it, he'd forgotten about Paul Cornell's implication that the Inferno Earth ruler was a version of the Doctor; "in my head, the Leader was just another in a long line of very human tyrants".