Millar acted as speechwriter for three[citation needed] British prime ministers, including Margaret Thatcher for whom he wrote the line "The lady's not for turning".[5] He was knighted after Thatcher became Prime Minister in 1979. He wrote the line, Where there is discord, let us bring harmony, which was one of her promises on arrival at 10 Downing Street.[3]
Millar was the son of a professional actress, Dorothy Dacre-Hill. Prior to becoming a full-time dramatist and then a speechwriter, he acted in a number of West End productions during and after World War II, in the company of luminaries as Ivor Novello, Alastair Sim and John Gielgud.[6] He also appeared in the 1943 war film We Dive at Dawn directed by Anthony Asquith. One of his most well-received productions was Abelard and Heloise featuring Keith Michell and Diana Rigg.[7]