As Flight Lieutenant Brian Cook he failed to defend the Conservative seat of Chelmsford at a by-election in April 1945 which was won by Ernest Millington for the short-lived Common Wealth Party. He was elected as member of parliament for Ealing South at a by-election on 12 June 1958.
In a by-election in April 1945, Flight Lieutenant Brian Cook lost his Conservative seat of Chelmsford to Ernest Millington, who represented the Common Wealth Party. He was later elected as a member of parliament for Ealing South at a subsequent by-election on June 12, 1958.