Blakenham was an Alderman of London County Council between 1937 and 1952 and fought in the Second World War with the Suffolk Yeomanry in Italy and was awarded the Legion of Honour and appointed an OBE.
He later held office under Macmillan as Minister of Agriculture, Fisheries and Food from 1958 to 1960 and Minister of Labour between 1960 and 1963.