Forgan, a member of the Labour Party, served on the Glasgow Town Council (1926-29) before being elected to represent West Renfrew in May 1929.
Oswald Mosley founded the New Party in 1931. Early supporters included Forgan, John Strachey, John Becket, Harold Nicholson and A. K. Chesterton, but in the 1931 General Election none of the New Party's candidates were elected.
In January 1932, Mosley met Benito Mussolini in Italy. Mosley was impressed by Mussolini's achievements and when he returned to England he disbanded the New Party and replaced it with the British Union of Fascists (BUF). In October, 1932, Mosley published The Greater Britain, his manifesto for a Fascist state.
Oswald Mosley appointed Forgan as his Director of Organization. He later served as deputy leader of the BUP. Forgan became disillusioned with Mosley's increasing anti-Semitism and worked as a spy for the British Board of Jewish Deputies. Forgan resigned from the BUP in 1934.
Robert Forgan died on 8th January 1976.