William Mainwaring (English politician) Burdett. Mainwaring had previously resisted Burdett's calls for an inquiry into prison abuses, particularly at Coldbath Fields Prison. Mainwaring was defeated by Burdett but the election was declared void in 1804 and in the following contest William's son George Boulton Mainwaring was elected. The result was reversed in favour of Burdett in 1805 and the back in favour of Mainwaring Junior in 1806. Mainwaring did not contest the 1807 election and Burdett was not elected. He died in 1821, leaving one son. William Mainwaring (English politician) William Mainwaring (6 Oct 1735 – 28 February 1821) was the MP for Middlesex
William Mainwaring Federation of Great Britain in 1924, but was narrowly defeated by A. J. Cook. Mainwaring polled 49,617 against Cook's 50,123 votes. Cook went on to win the post and vacated his previous post as miners' agent for the Rhondda district; Mainwaring was appointed to succeed him. He was one of two agents for the district, and with his fellow agent Alderman David Lewis, Mainwaring had to fight the attempts by members of the Communist Party of Great Britain to gain influence. In 1928, under Communist influence, the lodges of the Rhondda Miners' Federation called for a membership ballot to elect