Lord London

Lord London was a title in the inherited peerage of England that was held by several people on Earth. During the 22nd century it was given to at least two people, the most famous of whom waged a long and bitter war against Lord Haldoran.

Donna's father
One Lord London — whose name or number was unknown — was distinguished by the fact that he had a daughter named Donna. Along with the Eighth Doctor, he waged a war against Lord Haldoran and the Master].

Some time during the war, this London gave his seventeen-year-old daughter to Haldoran to marry to create peace. Haldoran tortured Donna and constantly attempted to impregnate her, until she was found infertile. He divorced her and took her cousin, Brittany, who bore him twelve children.

London shunned his daughter after learning of her infertility. He allowed her to go off and become a knight, yet thought of her safety in his last battle.

London was killed when one of his own men shot him for bargaining in a surrender. Little known to him or his men, Haldoran had been killed by Donna moments before.

Toby Barlow
After the death of this London, the Domains Haldoran and London were combined under a new Lord London, originally named Toby Barlow. He had been on Haldoran's council, and emerged as the most likely heir to both titles once the previous Lords Haldoran and London died fighting each other.

He also made a serious marriage proposal to Donna, but it was unclear whether she ever accepted it. (EDA: Legacy of the Daleks)