MACKWORTH, Herbert (1737-91), of Gnoll, Glam.

Published in The History of Parliament: the House of Commons 1754-1790, ed. L. Namier, J. Brooke., 1964
Available from Boydell and Brewer



2 Jan. 1766 - 1790

Family and Education

b. 1 Jan. 1737, o.s. of Herbert Mackworth.  educ. Westminster 1748; Magdalen, Oxf. 1753; L. Inn 1754, called 1759.  m. 13 May 1761, Elizabeth, da. of Robert Cotton Trefusis of Trefusis, Cornw., 2s. 1da.  suc. fa. 20 Aug. 1765; cr. Bt. 16 Sept. 1776.

Offices Held


Like his father, Mackworth was active in developing the industrial enterprises on the Gnoll estate: his main concern was with the Gnoll Copper Company, with works at Neath,1 which by 1777 appears in the London directories as having its headquarters at Monument Lane in the City. And in June 1781 Mackworth applied to the Treasury on behalf of the company for the right to supply the copper necessary for the coinage ordered for Ireland.2 He also extended the coal-mines on his estate, and founded and ran a local bank.

Mackworth controlled two of the Cardiff boroughs, but it was with the additional support of the Windsor interest that he was returned unopposed in 1766 and at all his subsequent elections. In Parliament he was thoroughly independent, and spoke very frequently on a wide variety of subjects. He appears in two of the three extant division lists as having voted with Opposition on the land tax, 27 Feb. 1767, though Newcastle in his list of 2 Mar. classed him as an Administration supporter. In the ensuing Parliament he voted with Opposition on the expulsion of Wilkes, 3 Feb. 1769, and the Middlesex election, 15 Apr. and 8 May, declaring on 3 Feb.:3 ‘My mind is distressed to give a vote ... I shall go against his Majesty’s ministers, but my principle is to support them.’ He again voted with Opposition on the Middlesex election, 25 Jan. 1770. On 22 Nov., criticizing an Opposition motion for the production of papers concerning the Falkland Islands dispute, he declared:4 ‘I have confidence in the ministers. I have acted against them, I have voted against them, and shall vote again, but I shall not upon this ground say I have no confidence.’ And though he voted with them on this occasion, he again opposed them on 13 Feb. 1771 over the settlement of the dispute. He once more voted with Administration over Brass Crosby, 27 Mar. 1771, but in Robinson’s first survey on the royal marriage bill, March 1772, he was listed as ‘doubtful, present’. When on 9 Feb. 1773 he voted with Opposition on the naval captains’ petition he was marked in the King’s list as a friend, and though he also voted with Opposition on the Middlesex election, 26 Apr. 1773, and on Grenville’s Election Act, 25 Feb. 1774, he was classed by Robinson in September 1774 as ‘pro’.

On 31 Oct. 1776, emphasising his position as an independent country gentleman, he said:5

He did not like to hear gentlemen so ready to find a plea for the Americans on every occasion ... He was ever most clearly against the House attempting to tax America as America was not represented in that House; but he thought it highly necessary to maintain that right; and that it was but reasonable America should contribute something in return for the millions she had cost this country. He spoke highly in favour of some of the gentlemen in Opposition, but applauded the ministry.

He does not appear in any of the minority lists, February 1775-December 1778, but in Robinson’s list on the contractors bill, 12 Feb. 1779, he is listed as ‘contra, present, friend’. He voted with Opposition over Keppel, 3 Mar. 1779, and his only other recorded vote during this Parliament was with Opposition on Dunning’s motion, though Robinson in his electoral survey of July 1780 counted him as an Administration supporter. He voted with Administration on Sir James Lowther’s motion against the war, 12 Dec. 1781, and on 14 Dec. told the House that he ‘had supported his Majesty’s ministers in the American war from the conviction they had the real interest of the empire at heart, and that the principle of the war was just, though the issue had been unfortunate’.6 But Mackworth was absent from the crucial divisions of February-March 1782, and apparently remained in Glamorgan, ignoring urgent summonses from Administration.7 He voted for Shelburne’s peace preliminaries, 18 Feb. 1783, and for Fox’s East India bill, 27 Nov. 1783. Early in January 1784 John Sinclair noted that he ‘might be secured by attention. If Sir William Dolben, Sir Henry Hoghton and he, could be got to speak in favour of the new India bill, which might be effected, it would be of the most material consequence.’8 But Robinson, in his list drawn up the same month, counted Mackworth as an opponent, and he voted against Pitt’s Administration. He now spoke far less frequently in the House, and rarely on matters of national interest.

In 1790 Mackworth was forced to retire in favour of John Stuart whose father, Lord Mountstuart, was no longer willing to acquiesce in his tenure of the seat.  He died 25 Oct. 1791.

Ref Volumes: 1754-1790

Author: Peter D.G. Thomas


  • 1. D. Rhys Phillips, Hist. Vale of Neath, 228, 238, 265-80, 311.
  • 2. PRO T29/50.
  • 3. Cavendish’s ‘Debates’, Egerton 217, p. 241.
  • 4. Ibid. 222, p. C.161.
  • 5. Almon, vi. 26.
  • 6. Debrett, v. 181.
  • 7. Sandwich to Robinson, 15 Feb. 1782, Abergavenny mss; Laprade, 41.
  • 8. Sinclair mss, Thurso East Mains.