Harriet Jones

Harriet Jones was the prime minister of Britain in the Doctor Who series.

During her first appearance, she was a backbencher. She helped the Doctor defeat the Slitheen in Aliens of London.

The 2 are shown to not exactly be on good terms with one another, but she is an ally to the Doctor, nonetheless.

During her next appearance, she had become Prime Minister of Britain. She was in The Christmas Invasion where Sycorax invaded Earth and, as an intension of enslaving half of its population, threatened the humans to surrender to their demands or they will coerce every person it A+ blood type to fall to their doom. The Doctor succeeded in defeated the alien race, but as they were leaving, their ship was destroyed, killing every single Sycorax on board. It was revealed that Harriet was the one responsible for it as she believed that was she did was for the good of everyone. After she left office, she returned again in The Stolen Earth, helping Torchwood, Sarah Jane Smith and Martha Jones, also known as the Children of Time, to contact and summon the Doctor to Earth after it was stolen by the Daleks. Their attempt would make all 4 factions easily detectable to the Daleks, but Jones masked the other 3's signals and only have her own be tracked by them. Afterwards, the Daleks found her and seemingly decimated her, but it was mentioned that she escaped her allihilation through a trapdoor in her house and sped away in a motorcycle.

Throughout her last 2 appearances, there was a running gag involved with her, to which everytime she would introduce herself, be it as Prime Minister or former Prime Minister, everyone else would follow up with "Yes, we know who you are".