Dickinson entered Parliament the year he was called to the bar and at the same time as his father became county Member. He presumably purchased his seat from Richard Troward, the then patron of Ilchester. He devoted his not inconsiderable abilities to the regular support of Pitt’s administration. On 3 Jan. 1798 he defended the assessed taxes bill as necessary for the security of the realm; on 11 Dec. in reply to opposition clamour for peace, he said that the time was inopportune. Pitt was sufficiently impressed to give him the opportunity to second the address (11 Nov. 1800), which he did in a long speech that showed a jurisprudent’s concern with general principles. On 19 Feb. 1801 he voted with opposition for inquiry into the failure of the Ferrol expedition. In June 1801 he supported his father’s efforts to thwart vexatious prosecution of the clergy for non-residence; and he or his father opposed additional reimbursements to coroners from the county rates, 8 Mar., 27 Apr. 1803. He secured a committee on the West Country clothiers’ petitions, 16 Feb. 1803, and on 6 Apr. moved for a bill to alter 13 statutes for their relief: ‘practical good and evident utility are the only just grounds on which the laws can be proposed to be amended with safety’. He went on to defend the bill against its West Riding critics, 27 Apr.
Dickinson had hitherto been well disposed to Addington’s administration. On 9 Mar. 1802 he condemned Bateman Robson’s tactics in opposition and on 13 Dec. applauded the commission of naval inquiry, which together with the peace and tax relief did the ministry credit. But on 3 June 1803 he voted with Pitt, soon afterwards married Pitt’s friend Lord Carrington’s niece and in March 1804 joined him in opposition to Addington. Speeches of 9 and 22 Mar. and his votes with Pitt in all the crucial divisions on defence that brought down Addington made his position clear, and on 30 Apr. he wrote to Pitt offering ‘to make a useful member of your administration’.
Dickinson would have been content to retain his Admiralty place under Lord Grenville, informing him through Lord Glastonbury: ‘My connection in politics is at an end by the death of the ever to be lamented Mr Pitt’. Glastonbury suggested that, with his father’s vote and his uncle Hans Sloane’s, he was a good recruit but, in the event, Grenville was prevented by the ‘great variety of claims of every sort’ from retaining him. Meanwhile he and his father and uncle had abstained on the first major division, 3 Mar. 1806, but on 30 Apr. he voted against ministers on the repeal of Pitt’s Additional Force Act. This was not decisive: Glastonbury described his views as ‘perfectly orthodox’ to Lord Grenville, 29 May, and in October Grenville offered to restore him to the Admiralty. He was expected to accept, but demurred because he wished to win the county seat, unhindered by office. He might have retained Lostwithiel, or (in office) come in for Queenborough, but hankered for a respectable seat.
Dickinson, still listed adverse to the abolition of the slave trade in 1806, admitted that he was impressed by the moderation of the abolition bill, 9 Mar. 1807, and, although he still had reservations, did not oppose it. On 23 Mar. it was he who put the question to Viscount Howick which enabled the latter to inform the House that the King was forming a new ministry. According to Lady Holland, ‘Dickinson did the business very ill, and so clumsily that he did no good by his query’. He had leave of absence to attend quarter sessions and was expected to miss Brand’s motion, but he attended to vote for it, 9 Apr.
On 26 June 1807 Dickinson and his father-in-law voted with ministers on the address;
Returned unopposed in 1812, Dickinson remained independent. He denounced Burdett for ill-founded allegations about aggrieved petitioners, 9 Mar., 5 May 1813; but supported Romilly’s bill to abolish capital punishment for some cases of theft, 26 Mar. He supported the sinecure regulation bill, 29 Mar., and was chairman of the committee on the Admiralty registrars bill. He voted for the Catholic relief bill on 13 May, but against on 24 May 1813 (abstaining thereafter); and on 5 July denounced the stipendiary curates bill as an encroachment on the freehold of the church establishment. He next emerged as a supporter of the disbandment of the militia, 28 Feb. 1815; of a committee on the Bank, 2 Mar.; and as a critic of the civil list, 14 Apr., 8 May, and of the property tax 19 Apr., 5 May 1815: on the last occasion he threatened an amendment to relieve the agricultural interest, but did not appear in the minority. In 1816 he opposed the army estimates and the renewal of the property tax, defending petitions against it, 29 Feb.,
Dickinson headed the poll in 1818, when his coalition with Gore Langton against the ministerial candidate cost him over £7,000. He did not sign the requisition to Tierney to lead the opposition. He voted for the addition of Brougham to the Bank committee, 8 Feb. 1819, and against the Windsor establishment, 22 and 25 Feb. He gave a qualified support to two Somerset petitions for agricultural protection, 26 Feb. He was, as in the two previous sessions, a member of the Poor Law committee. He supported criminal law reform, 2 Mar. He was in the minorities on excise informers, the junior lords of Admiralty and the royal household bill that month. He also opposed the equalization of coal duties, 5 Mar., 20 May. He gave his ‘hearty support’ to Tierney’s censure motion, 18 May, complaining of a ‘government of departments’ and calling for a broad administration to avert a situation reminiscent of that of France in 1789. He wished soon afterwards to move for an inquiry into the state of the country. Lord Grey was informed:
Dickinson stands high with the country and is not considered to be either a ministerial or opposition Member and therefore our friends in the House would not be committed by the course he would take at the same time that I perceive they would give him every support in their power in the furtherance of his object.
Nothing came of it and on 10 June he was in the majority on the foreign enlistment bill. On 14 June he presented Somerset petitions against the proposed wool duty, but on 18 June objected to the protective duty on imported wool as the clothiers required ‘a certain portion of foreign wool’.
Dickinson, now in command of the East Somerset yeoman cavalry, was an alarmist in the last session of the Parliament of 1818. He favoured the seizure of arms bill, 16 Dec. 1819, and on 20 Dec. expressed his approval of all the ministerial measures designed ‘to stem the current of anarchy and rebellion’. He died at Naples, 19 Jan. 1837.
