MOSTYN, Sir Thomas, 6th bt. (1776-1831), of Mostyn, Flint. and Gloddaeth, Caern.

Published in The History of Parliament: the House of Commons 1820-1832, ed. D.R. Fisher, 2009
Available from Cambridge University Press



8 Nov. 1796 - 12 June 1797
8 Nov. 1799 - 17 Apr. 1831

Family and Education

b. 20 Oct. 1776, o.s. of Sir Roger Mostyn†, 5th bt., of Mostyn and Gloddaeth and Margaret, da. and h. of Rev. Hugh Wynn, DD, preb. of Salisbury, h. of her uncles Robert Wynne† of Bodysgallen, Caern. and Evan Lloyd Vaughan† of Corsygedol, Merion. educ. Westminster bef. 1793; Christ Church, Oxf. 1793. unm. 1da. illegit. suc. fa. as 6th bt. 26 July 1796. d. 17 Apr. 1831.

Offices Held

Sheriff, Caern. 1798-9, Merion. 1799-1800.

Lt.-col. commdt. Flint fusiliers 1803.


Mostyn was one of Wales’s largest landowners, with estates and influence in Caernarvonshire, Flintshire, Merioneth and elsewhere. His life had long been governed by his passion for the chase, which he pursued in the company of his brother-in-law Sir Edward Pryce Lloyd* and their kinsman, the hunting parson Griffith Lloyd, in North Wales and the Wirral, and as master of the Bicester Hounds in Gloucestershire, Oxfordshire and Warwickshire.1 His engagement books record more visits to operas and London theatres than to the Commons, where he had represented Flintshire almost continuously since 1796, but he noted the debates and divisions he considered important, dined regularly at Boodle’s, and was attuned to the needs of his constituents, whose petitions and business he either attended to quickly himself or delegated to Lloyd. He made no major speeches.2

Mostyn apparently failed to sign the requisition for a Flintshire county meeting to mark the death of George III and remained in London until shortly before his election at Flint, 16 Mar. 1820. His addresses contained no statements of policy, but his Whiggism and support for Catholic relief were well known. He afterwards headed the requisition for a meeting to petition for a St. Asaph enclosure bill, and announced a 25 per cent reduction in his rents.3 In Parliament he divided consistently but sporadically with the Whig opposition to the Liverpool ministry, doing so on the civil list, 5, 8 May, and the appointment of an additional Scottish baron of exchequer, 15 May 1820. He was named to the 1820 and 1821 select committees on the administration of justice in Wales. He remained central to Whig activity in Flintshire, where he presided at the Agricultural Society dinner in October 1820 and attended the assizes and militia exercises.4 He supported the 1821 parliamentary campaign on behalf of Queen Caroline, divided as hitherto for Catholic relief, 28 Feb. 1821, 21 Apr., 10 May 1825, and paired, 22 Apr. 1822, and voted for parliamentary reform, 2 June 1823. He received a month’s leave on account of ill health, 13 Apr. 1821. He voted to omit arrears from the duke of Clarence’s grant, 2 July 1821. Later that month Dr. William Browne accused him of abusing his position as a family friend by violating his daughter. Possibly though the intervention of Lord Jersey, Mostyn avoided both marriage and legal action. A bachelor of nearly 45, he already had a 12-year-old daughter, Elizabeth, tucked away at Catherine Cruickshanks’s establishment in Boulogne.5

He failed to attend the Flintshire agricultural distress meeting, 17 Apr., but he presented their petition for government action, 24 Apr., and voted to repeal the salt tax, 28 June 1822. He had recently divided for reductions in diplomatic expenditure, 16 May, to condemn the growing influence of the crown, 24 June, and for inquiry into the lord advocate’s treatment of the Scottish press, 25 June 1822.6 During the recess he paid the customary £200 a year for Elizabeth’s care and prepared for the hunting season, which was marred for him by ‘shoulder lameness’.7 He paired in condemnation of the indictment of the Methodist missionary John Smith in Demerara, 11 June, and divided against the Irish insurrection bill, 18 June 1824, and the duke of Cumberland’s annuity, 6 June 1825. He presented the grand jury of Flintshire’s petition against repealing the usury laws, 18 Apr. 1826. His return at the general election in June was unopposed, and he afterwards saw to River Dee Company business, in which as the proprietor of the loss making Mostyn Quay, he had a vested interest.8 He had given his interest in Caernarvon Boroughs to Lord Anglesey, and was to do so again in 1830.9

Increasingly troubled by gout, Mostyn now rarely attended the Commons. He presented his constituents’ petitions for repeal of the Test Acts, 7 June 1827, 19 Feb. 1828, but is not known to have spoken or voted on the issue. He paired for Catholic relief, 12 May 1828, and presented petitions against restricting the circulation of one and two pound notes, 2 June, and for an increase in coroners’ allowances, 7 June 1828. Ill with rheumatism, he ordered Mostyn to be closed and returned to London in February 1829 to monitor the progress of Catholic emancipation, for which he voted, 30 Mar. He frequented the Welsh Club, attended the Commons, 24 Feb., 18 Mar., and presented, but refused to endorse Flintshire anti-Catholic petitions, 26 Feb. Citing ‘pressure of business’, he declined to attend anti-Catholic meetings, 20 Mar., and the Flintshire Ultras accordingly turned to his brother-in-law Sir Robert Williames Vaughan* for support.10 Both were distressed by the death following a hunting accident of their nephew Griffith Lloyd, 26 Mar. 1829.11 Silt had become a persistent problem at Mostyn docks, and Mostyn hoped that the contentious Dee Ferry road, for which he presented petitions, 6 May 1829, would improve the profitability of his iron works and coal and lead mines. The Ultra Commons leader Sir Richard Vyvyan listed him among the supporters of Catholic emancipation whose attitude to a putative coalition government in October 1829 was ‘unknown’.

Mostyn spent the summer of 1829 in London and at the races, often in the company of the sisters of William Lewis Hughes*: Mary, with whom his name was now linked, and Martha, the widow of his friend Cynric Lloyd, who later married Colonel Wyatt.12 He borrowed an additional £120,000 from the Law Life Assurance Society as security for his mortgage debts to Thomas Coutts and Company, 26 Aug., and when he returned to Mostyn in September he found much county business awaiting him and came under pressure to make new arrangements for Elizabeth, who was 21 in November.13 Before leaving for Leamington, where he took a house for the hunting season, he contributed to local charities and celebrated the birth in December 1829 of his great-nephew, Lloyd’s grandson Thomas Edward Mostyn Lloyd (d.1861).14 He was a requisitionist for the Flintshire distress meeting, 8 Feb., and supported their petition; but another adopted by the Holywell vestry troubled him, and he discussed the case with the home secretary Peel before arranging for Lloyd to present both petitions on 15 Mar. 1830.15 He voted against the proposed expenditure on Woolwich Academy, 30 Apr., and public buildings, 3 May, and for information on privy councillors’ emoluments, 14 May. He was said to favour abolition of the Welsh judicature and reform of the assize system, but when the administration of justice bill that effected it was introduced he presented and endorsed Flintshire’s hostile petition for continuation of the assizes as hitherto, 12 May. On the hustings at the general election in August 1830 he referred to the ‘unpleasant impression’ the bill had given and said that he hoped it would prove better than expected.16 Mostyn’s finances remained troubled, and after meetings with his executors, Sir Edward Pryce Lloyd and Richard Parry, and the bankers William Hughes and Owen Williams*, he took out a modified deed to cover an aggregate mortgage debt of £420,000, to which the attorney-general Sir James Scarlett* contributed £60,000, the barrister Thomas Atkinson £45,000 and the queen’s solicitor J.W. Farrer £15,000, 30 June.17 Before the dissolution precipitated by George IV’s death, he attended a meeting of the revived Whig opposition at Lord Althorp’s*, 5 July, and presented Flintshire’s petition against renewing the East India Company’s charter, 9 July 1830. On the hustings at Flint, 7 Aug., when he was returned unopposed and every public house was thrown open, he said that he shared local concern over the monopolies of the Bank of England and the East India Company, supported the abolition of slavery, and advocated tax cuts and rigid economy as the only means of bringing back ‘the good old times’.18 After visiting the county sheriff and the bishop of St. Asaph, he attended the opening of the Liverpool-Manchester railway before returning to London, having apparently thwarted his daughter’s plan to visit him there while she was in England that summer.19

The Wellington ministry listed Mostyn among their ‘foes’, but he was absent from the division on the civil list which brought them down, 15 Nov. 1830. By February 1831, when Martha Wyatt protested that Mostyn had encouraged gossip that she had colluded in making her sister his resident mistress, he was too ill and dependent on opiates to consider going to the opera or to attend to parliamentary business, which then included the Holyhead roads bill.20 He had delegated his Flintshire concerns, including reform petitions, to Lloyd; but he went to the Commons, 22 Mar., to vote for the second reading of the Grey ministry’s reform bill. His engagement book records his intention of being there when it was considered in committee on 18 Apr., but he died at 10 pm on the 17th of ‘gout in the stomach and head’. He had used his seat in church for the first time, 27 Mar. 1831. His body was taken to the family vault at Llanrhos for burial.21 Prices realized from the sale of his racing stud in July proved disappointing.22 His will and settlement, dated 26 Aug. 1829, were proved under £60,000 in Flint and London and administered by Richard Parry and Lloyd, to whom he left his estates in trust. Lloyd’s eldest son Edward, to whom he left £3,000, succeeded him as Member for Flintshire and took the name of Mostyn as directed. Bequests of £20,000 to his daughter, who married Charles Clements Brooke of Leamington Priors, Warwickshire, £15,000 to Cynric Lloyd, and £10,000 each to his executors, sisters and named nephews and nieces overburdened the Mostyn estates, which were already encumbered by half- yearly mortgage interest payments of £2,400.23 The baronetcy being extinct, Lloyd was raised to the peerage at the coronation in September 1831 as Baron Mostyn.

Ref Volumes: 1820-1832

Author: Margaret Escott


  • 1. T.A. Glenn, Fam. of Mostyn of Mostyn, 173-7.
  • 2. UCNW, Mostyn of Mostyn mss 251-64; HP Commons, 1790-1820, iv. 641.
  • 3. Chester Chron. 25 Feb., 3, 10, 17, 24, 31 Mar., 7 Apr.; Mostyn of Mostyn mss 7898; Gent. Mag. (1820), i. 555.
  • 4. Tracts on Agriculture: Flint Agric. Soc. (1825), passim; Chester Chron. 20, 27 Oct. 1820.
  • 5. Mostyn of Mostyn mss 7424-8, 7433.
  • 6. Salopian Jnl. 10, 24 Apr. 1822.
  • 7. Mostyn of Mostyn mss 251, 7431.
  • 8. Ibid. 251, 7431.
  • 9. UCNW, Plas Newydd mss i. 228, 248, 287, 382, 410, 434, 457; Mostyn of Mostyn mss 7451.
  • 10. Mostyn of Mostyn mss 256, 7450; N. Wales Chron. 26 Feb. 1829.
  • 11. Shrewsbury Chron. 3 Apr. 1829.
  • 12. Mostyn of Mostyn mss 257; NLW ms 2795 D, C. to H. Williams Wynn [1826].
  • 13. Mostyn of Mostyn mss 258, 3417, 7453-5.
  • 14. Ibid. 258; Chester Courant, 1, 8 Dec. 1829.
  • 15. Flint RO D/KK/467-9; Mostyn of Mostyn mss 7456-8; Chester Courant, 2, 9 Feb. 1830.
  • 16. PP (1829), ix. 413; N. Wales Chron. 23 Apr. 1829; Chester Courant, 10 Aug. 1830.
  • 17. Mostyn of Mostyn mss 263, 3418.
  • 18. Ibid. 263; Chester Courant, 10 Aug. 1830.
  • 19. Mostyn of Mostyn mss 7459-61.
  • 20. Ibid. 264, 7464.
  • 21. Ibid. 264, 7902, 7903; Caernarvon Herald, 23 Apr.; Chester Courant, 26 Apr. 1832.
  • 22. Chester Courant, 5 July 1831.
  • 23. PROB 11/1788/407; IR26/1264/316; Mostyn of Mostyn mss 265, 266, 3305, 7477-88; Flint RO, Mostyn mss D/M/3596-9, 3869, 3879, 3870.