Remembered by his colleagues in the Linnean Society as ‘thoroughly honourable and upright in all his dealings, a steady man of business, a liberal and active country gentleman, a warm friend, and a zealous and enlightened contributor to Natural Science’, Dillwyn made less impact in his parliamentary than in his scientific career.
Alongside his scientific endeavours, Dillwyn, ‘a man of considerable energy’ with ‘a versatile and vigorous mind’,
In 1807 Dillwyn had to leave the Society of Friends after marrying a non-Quaker, Mary Adams, the illegitimate daughter and heiress of Colonel John Llewelyn of Penllergare.
At the 1832 election Dillwyn was returned unopposed alongside Talbot, other potential candidates having withdrawn. He declared his support for equitable commutation of tithes, but announced his ‘strong dislike’ of the ballot and his opposition to further franchise extension. He argued that any alteration in the corn laws ‘would be the ruin of the country’: ‘our agricultural and commercial interests are so inseparably blended that neither can ever flourish while the other starves’. A prominent member of the local anti-slavery society, he supported the abolition of slavery, but cautioned against the ill effects of ‘any immediate or abrupt abolition’.
Dillwyn is not known have spoken in debate, but he served on the select committees on the Londonderry and Monaghan election petitions, and the 1834 committee which considered whether the number of houses occupied by public officials at public expense could be diminished.
A fairly diligent attender, Dillwyn’s views were generally in sympathy with the Whigs: he divided against further electoral reform, but supported efforts to remove religious disabilities, dividing for the second reading of the Jewish disabilities removal bill, 29 May 1833, and the admission of Dissenters to universities, 20 June 1834. However, his voting patterns confirm the view of one obituary that ‘he exhibited more freedom from the trammels of party, more independence than most men of his time’.
Dillwyn’s independent streak led the Examiner to list him among the ‘doubtful men’ after the 1835 election, describing him as formerly ‘a good Reformer’, but now ‘a trimmer’ who had ‘gone over to the enemy’.
Dillwyn retired at the 1837 election, declining a baronetcy which Liberal ministers offered if he would stand against the Conservative candidate, an offer which suggests that despite the Examiner’s concerns, his broad party loyalties were not in question.
Dillwyn left a life interest in his estates to his wife, with his second son Lewis then to inherit.
