At the general election of 1820 Williams again returned himself on the well-established family interest for Great Marlow, which lay across the Thames from his Berkshire residence. He gave the other seat to his elder son, Thomas Peers Williams, having set aside Pascoe Grenfell*, his colleague of 17 years and his partner in the copper processing business on which his substantial fortune was based. By 1829 he had fallen out with Grenfell and completely withdrawn from the enterprise.
He paired with opposition on the Queen Caroline affair, 26 Jan., 6 Feb. 1821. He was given three weeks’ leave on account of illness, 12 Mar., but was in Hume’s minority of 29 for a revision of public salaries, 30 Mar. He got a fortnight’s leave to deal with urgent private business, 7 May. He was present to vote in a minority of 14 against the duke of Clarence’s annuity bill, 25 June, and for Hume’s call for economy and retrenchment, 27 June 1821. He divided for abolition of one of the joint-postmasterships, 13 Mar., 2 May, and for inquiries into the board of control, 14 Mar., and the government of the Ionian Islands, 14 May, and was in small minorities to reduce the navy estimates, 18 Mar., and adjourn proceedings on the aliens bill, 14 June 1822. His only recorded votes in the next two sessions were for repeal of the assessed taxes, 18 Mar., in a minority of 37 for the abolition of whipping as a punishment, 30 Apr. 1823, and to postpone consideration of the grant for Windsor Castle repairs, 5 Apr. 1824. He paired on the government side against inquiry into the prosecution of the Methodist missionary John Smith in Demerara, 11 June 1824. After defaulting on a call of the House, 28 Feb., he voted for Catholic relief, 10 May, and against the duke of Cumberland’s annuity, 10 June 1825. He divided against giving the president of the board of trade a separate ministerial salary, 7 Apr. 1826.
At the general election two months later Williams encountered a challenge to his control of Marlow from resentful independents, who took up James Morrison*, a wealthy London silk merchant of advanced liberal views. He topped the poll and brought his son safely in with him, but Morrison polled respectably, and in 1827 and 1828 Williams vengefully evicted those of his borough tenants who had cast a hostile vote.
Williams was initially placed among the ‘good doubtfuls’ by ministers, but he was subsequently deemed to be a ‘friend’; he was in their minority in the decisive division on the civil list, 15 Nov. 1830. He voted against the second reading of the Grey ministry’s reform bill, 22 Mar., and for Gascoyne’s wrecking amendment, 19 Apr. 1831, and that month tried unsuccessfully to block a Marlow meeting in its support. At the general election called after the bill’s defeat he and his son were only narrowly returned ahead of their opponent of 1830. Williams was absent throughout ‘in consequence of a dangerous indisposition’, which was thought likely to carry him off.
