Williamson was a direct descendant of the Nottinghamshire Royalist baronet, Sir Thomas Williamson (1609-57), of East Markham, whose namesake son had acquired the Monkwearmouth estate on the Durham (north) bank of the River Wear through his marriage with the Northumberland heiress Dorothy Fenwick of Brinkburne. They intermarried afterwards with the Durham families of Hedworth, Hopper, Huddleston, Lambton and Liddell, settled at Whitburn and held the shrievalty without interruption from 1723 until the death of Williamson’s father in 1810. His subsequent upbringing was entrusted to his mother and her co-trustees Ralph Lambton†, the recorder of Newcastle Robert Hopper (Williamson), and the Durham attorney Richard Scruton. Williamson took control of the heavily encumbered Whitburn estate in 1819 and declined the shrievalty on financial grounds that year. As his father had directed, he provided £9,000 settlements for his sisters, Maria, wife of the banker David Barclay*, and Sophia, who in 1823 married the Whig Thomas Dundas* Following his own marriage in 1826 to his neighbour Lord Ravensworth’s daughter, he economized by spending two years on the continent.
Williamson voted for the reintroduced reform bill at its second reading, 6 July, and steadily for its details, casting wayward votes only for the total disfranchisement of Russell’s borough of Saltash, which ministers no longer pressed, 26 July, and the transfer of Aldborough to schedule A, 14 Sept. 1831. He contradicted the anti-reformers’ arguments against the separate enfranchisement of Gateshead, 5 Aug. 1831, 5 Mar. 1832. He divided for the reform bill’s passage, 21 Sept., the second reading of the Scottish bill, 23 Sept., and Lord Ebrington’s confidence motion, 10 Oct. 1831. When Sunderland (27 Oct.) and the county (31 Oct.) met to protest at the bill’s defeat in the Lords, he defended the ministry and the bill, praised Durham as one of its authors and was thanked for supporting it.
Testifying to its local unpopularity, he presented petitions against the general register bill, 18 Oct. 1831, 31 Jan., and was added to the select committee on the measure, 27 Mar. 1832. He spoke in favour of amending the anatomy bill, 11 Apr. Williamson hoped to make his estate profitable by mining coal and building a railway and harbour at Sunderland, for which Brunel was the engineer, and he conducted constituency business along commercial rather than party lines. Backed by petitions from Sunderland and north Durham, he opposed the rival South Shields and Monkwearmouth railway bill, 14, 16 Feb., 6 Mar., and having failed to kill it (by 9-55), 14 Feb., he secured its referral to a committee of appeal (by 37-22), 26 Mar. Assisted by his Dundas relations, he led the opposition to the associated Sunderland (South Side) docks bill, backed by the corporation and the Durham Member William Chaytor, 27 Feb., and engineered its defeat in committee (by 10-7), 2 Apr. The publication of the division list by the Durham Chronicle became the subject of breach of privilege proceedings, 16 Apr., 7 May.
