President of Great Britain (Rise of the Cybermen)
From Tardis Wiki, the free Doctor Who reference
The President of Great Britain on a parallel Earth in 2007 was friends with Peter and Jackie Tyler.
John Lumic attempted to sell him his immortality concept, not just to Great Britain, but hopefully commercially, the President refused to support the proposal for being obscene and unethical. Affronted, Lumic had him murdered by one of many Cybermen who crashed Jackie Tyler's birthday party. (TV: Rise of the Cybermen)
He was succeeded by Harriet Jones, who remained in office into 2010. (TV: Doomsday)