Margaret Thatcher was 'UK's greatest prime minister' 8 April 2013 Last updated at 13:29 Help Speaking to The World At One, Lord Bell, her friend and colleague, said: "It is a very sad day indeed. I worked very closely with her from the moment she became leader right through until she resigned, and she was the most extraordinary woman. It was a great privilege to have worked for her and an even greater privilege to live in a country she ran. She'll probably be remembered as the greatest prime minister we've had. I don't think we'll ever see the like of her again.