Captain Mainwaring often a sympathetic subtext to his own personal neuroses; it is apparent several times that he devotes his energies to his Home Guard unit for a sense of comradeship and purpose lacking in other parts of his life, such as his career and marriage. On one occasion when his men spurned a parade to play darts against the ARP he expressed bewilderment, saying coming to the platoon is "the highlight of my day". It is frequently implied that he is trapped in a loveless and unhappy marriage to Elizabeth, his unseen wife, who is domineering, neurotic and withholding of affection.
William Mainwaring declared to be in the interests of workers of Britain. Mainwaring became a staunch opponent of Welsh nationalism. In 1955 he denounced the assumption that the English "were in some peculiar way wholly foreign and alien to Wales", and ridiculed basing a nation on "poets, preachers and musicians". He supported reform of the system of leasehold ownership to allow leasehold tenants to buy their freeholds, attacking the sale of estates to financiers. After being little active in his last Parliament, Mainwaring announced his retirement a year before the 1959 general election. He lived to the age of 87. William Mainwaring