He didn't desire any further political power, and went on to serve on a number of government committees, including those on civil aviation, economies in the fighting services, and co-ordination between the navy, army, and air force. During 1924 and 1925, Weir chaired the committee on electricity supply to plan the rationalisation of the United Kingdom's electrical power industry. His conclusions led to the Electricity (Supply) Act 1926, and the creation of the National Grid and the Central Electricity Board. He was appointed to the Order of the Bath as a Knight Grand Cross in 1934.