1. The Ottoman Empire was crumbling when the 1900's came around. England was head superpower at that time. U.S. was getting on it's feet.
2. British was already friends with Iran in the 1900's when the Shah's father control the country.
3. You might want to check your history b.
Lol. If they were friends I guess you could say everywhere Britain has invaded the other side were "friends." Britain and Russia dictated borders in Iran in the 1800's and had influence even past Churchill.