Winston Churchill was perhaps Britain's greatest Prime Minister. He led the country through World War II, at times standing alone against Nazi Germany.
On some unknown occasion in the past he befriended the Doctor and is the only person known to be able to phone the TARDIS and ask for his help. Churchill is famously hard-headed, being willing to go to almost any lengths to defeat the enemy and is also interested in any new technology that might help the fight, two qualities which led him into thinking the Daleks might be the solution to Britain's desperate plight. But his practicality and indomitable spirit mean that he can also become one of the monsters' deadliest foes. He and the Doctor have an easy friendship, one steady, the other mercurial. They're similar in a lot of ways.