Dent was descended from an old Westmorland family, with property in the Appleby area. His father, the son of the youngest son of Robert Dent of Trainlands (1651-1702), was said to have started life as a local schoolmaster before being taken on as a clerk in the London bank of Child & Co. at Temple Bar. He became a partner in 1763, prospered and acquired a residence at Clapham as well as his town house. John Dent, who was to become a partner in the bank in 1795, successfully contested Lancaster in 1790. He may have gained an introduction there through Sarah Child, widow of his father’s late partner, who married Lord Ducie, a former Member for the borough, in 1791. He built up a strong interest and retained the seat at the next four general elections, fighting expensive contests in 1802 and 1807. About 1791 Robert Dent bought a share in the manor of Cockerham, six miles south of Lancaster, but it does not appear that he or his son had a permanent residence there. John Dent later acquired a villa on the Hampshire coast, where he seems to have lived during the parliamentary recess.
He was an active and conscientious Member, described in 1795 as ‘not a first-rate orator’, but ‘considerably above a degree of mediocrity’.
As befitted the Member for a slaving port, Dent was a determined opponent of slave trade abolition. On 26 Feb. 1793 he argued that abolitionist principles, ‘however they might be suited to England, were destructive of the property of the planters’ and that ‘people should be prepared for liberty before they could enjoy it’. Some of his many other pronouncements on the subject were that abolition was an infringement of Magna Carta, 7 Mar. 1796, and that the grievances of the slaves no longer existed, as the Liverpool merchants (with whom he strengthened his ties by his marriage to the sister-in-law of Isaac Gascoyne) had done everything possible to improve conditions on the middle passage, 1 Mar. 1799.
Dent, who in 1794 carried through a bill to expedite the administration of oaths at parliamentary elections (34 Geo. III c.73), spoke frequently on financial and commercial questions. He opposed the bill to prevent the working of canals during harvest time, 10 Apr. 1793, because it would deprive hundreds of navvies of their livelihood; called for a total prohibition of hair powder, 23 Mar. 1795, because soldiers used vast quantities of flour and servants stole it for this purpose, thereby endangering the food supply; objected to the bill protecting bankers from depredation by their clerks, 30 Mar. and 8 June 1795, on the grounds that it added to the already immense code of penal law and overlooked the basic problem of the clerks’ paltry salaries; and successfully opposed a bill to prevent the stealing of pewter pots, 13 and 20 Apr. 1796, because it would tempt the industrious poor to waste their wages in the public house rather than drink at home.
On the franking regulation bill, 11 Mar. 1795, Dent bridled at the insinuation that Members had abused their privileges en masse, but failed in his attempt to secure information on the subject. His motion of 13 Apr. for inquiry into abuses of franking in the public offices was carried by 53 votes to 41 and, although he did not get very far with the issue, being ‘unexpectedly’ opposed by ministers, on 20 May he exposed the extent and cost to the country of these malpractices. On 8 Feb. 1796 he confirmed his intention of proposing a tax on dogs, the proceeds of which he envisaged as being ‘appropriated solely to the relief of the poor’. He brought it forward on 5 Apr. 1796 with an alarming tirade against dogs which, along with later speeches on 15, 25, 27 Apr. and 12 May, was joyously seized on by the opposition wits and earned him the lifelong soubriquet of ‘Dog’ Dent. Pitt eventually came out against the plan as it stood and reintroduced it as a revenue earning measure.
Dent defended the Bank of England, 19 Dec. 1796 and 28 Feb. 1797, when he complained that ‘nothing but personal animosity had passed’ in the debate on the appointment of the secret committee, ‘from which he inferred that the Ins wanted to keep in, and the Outs to get in’. His statement that the Bank was equal to all difficulties but the exigencies of ‘a war wantonly made against us by a people who had denied the existence of a Being’ provided Sheridan with a target for his wit. He supported the suspension of cash payments, but wished the issue of bank-notes to be limited, 22, 24 and 27 Mar., and was a teller for the majority against Pulteney’s motion for the establishment of a new Bank, 30 May 1797. He opposed Pitt’s proposal to give a bonus to subscribers to the loyalty loan, 31 May, and, when rebuked by Rose for his allegation that some of Pitt’s advisers were guilty of jobbing, he replied:
He had supported the measures of ... [Pitt] ... because he thought he deserved his confidence, and while he thought so, he should continue to support them; but he could not think equally favourably of many who were near him.
This stand earned him the praise of The Times, where it was stated that Dent stood to gain financially from the bonus, as his firm had invested £50,000 in the loan.
Pitt’s resignation disturbed Dent, who on 16 Feb. 1801 demanded an explanation for ‘this sudden desertion of his office, when united wisdom and vigour were necessary to save the state from ruin’. He joined opposition in calling for inquiry into the Ferrol expedition, 19 Feb., supported an attempt to increase a quorum of the House to 60, 18 Mar., and voted for Grey’s censure motion, 25 Mar. 1801. He set his face against Elford’s country banks forgery bill, 14 May and 9 June, when he remarked that transportation would be just punishment for bankers who defaulted on their bills. He had reservations about the redemption of Exchequer bills, 16 Nov. 1801, but supported it ‘to give all the necessary power to ministers’ in case France broke the peace. On the bread assize bill, 2 and 7 Dec., he stated his wish for a more comprehensive plan, including the establishment of mills under parochial control, and he was strongly in favour of the continued prohibition of distillation from corn, 27 Nov., 9 and 14 Dec. 1801.
Dent grew increasingly dissatisfied with the Addington administration, particularly on commercial questions, and in the session of 1802 he and his brother-in-law began to co-operate with the ‘new opposition’. After discussions with him on the state of the nation in February, French Laurence told Earl Fitzwilliam that Dent ‘thinks with us’.
On Pitt’s return to power, Dent was initially listed under ‘Grenville’, but he warmly supported the additional force bill, 8 June, and in September 1804 was listed among the ministry’s supporters. He was a teller for the minorities against the slave trade abolition bill, 7 and 25 June, and condemned it out of hand, 12 and 27 June. The same day he dismissed the claims for redress of the calico printers, advanced by Sheridan, and he welcomed the counterfeit dollars bill as a boon to bankers, 2 July 1804. Thereafter, his contributions to debate became markedly less frequent. He voted against the censure of Melville, 8 Apr., and replied to Sheridan’s attack on the government on the question of proceedings against the printer of the Oracle, 2 May. After John Jeffery, Member for Poole, had moved for papers to support his vendetta against St. Vincent’s naval administration, 10 May, Dent moved for a return of naval promotions 1795-1804, ‘in order to probe things to the bottom, and draw a comparison’ between St. Vincent and Earl Spencer. The motion, amended to cover the period 1793-1805, was agreed to. After Sidmouth’s resignation from the ministry, Dent had hopes of a junction between Pitt and the Foxites and tried to promote it with a dinner, but nothing came of it. In July 1805 Pitt, at Canning’s instigation, offered him a baronetcy, but he declined it, so he told Canning, on finding that his wife ‘has a great ambition to be called Mrs Dent, without any addition or alteration’.
Dent opposed the ‘Talents’, voting against the repeal of the Additional Force Act, 30 Apr., and the American intercourse bill, 17 June 1806. When Jeffery renewed his ill-fated attack on St. Vincent, 10 May, Dent seconded the motion for inquiry but, probably primed by Canning, he did not pledge himself to support Jeffery’s object and expressed a conviction that St. Vincent’s conduct ‘would stand fully vindicated’. He complained of the effects of the assessed taxes on holders of small annuities, 9 June, seconded Mildmay’s motion for a vote of thanks to the volunteers, 11 July, taking the chance to attack Windham’s defence plans, and warned against hasty action on the proposed distillation of sugar, 30 Dec. 1806. He was one of the die-hards who voted against the slave trade abolition bill, 23 Feb. 1807. He spoke against Sheridan’s calico printers bill, 23 Apr. 1807, supported the Portland ministry while Canning remained a member of it and derided Petty’s attempt to salvage his sinking fund scheme, 14 July. Much vexed by frivolous petitions against his return after the general elections of 1806 and 1807, he raised the matter in the House, 22 July, and got leave to introduce a bill to stiffen the regulations governing recognizances, 6 Aug., but it foundered two days later for want of a quorum. His next reported speech was not made until 13 June 1809, when he justified the taxation of foreign money invested in public funds. Earlier in the year he had made himself known at Poole, along the coast from his villa, by canvassing for the unsuccessful candidate at the by-election caused by Jeffery’s appointment to office, and he subsequently announced that he would not stand for Lancaster at the next general election.
Dent ‘delivered himself up hand and foot to Canning’ when the latter resigned and remained one of his ‘little senate’ during his period out of office. He was said to be ‘barking very loud’, but failed to persuade his brother-in-law to join him. He voted with Canning for the address, 23 Jan. 1810, but was absent from the division on the Scheldt expedition three days later. One ministerialist reported that ‘Dent runs everywhere with a double prophecy, that the government must fall’ but also that ‘Canning alone can save it if offered a carte blanche’, and he voted against government in their defeats on Lord Chatham’s narrative, 23 Feb. and 5 Mar. He voted with government in the first three divisions on the Scheldt, 30 Mar., acting as a teller in the second and, according to Canning, who set his friends free for the final division on the exculpatory resolution on the retention of Walcheren, he then went away, though there was a report that he had voted against ministers.
At the general election of 1812 Dent canvassed Poole with some confidence and tried to entice his fellow Canningite Huskisson to join him, but, claiming that ‘the government and Carlton House have moved heaven and earth against me’, he had to abandon the attempt. Canning was willing to offer him his surplus seat for Petersfield, but he must have declined it, even though he was said to be ‘very sore at having no seat’ and to be eloquently vilifying the Prince Regent ‘for having him beaten’ at Poole. He remained attached to Canning, who in 1813 planned to ‘descend to the coast, where Dent, like another Scylla, barks from his cliff at the passing sail’. After Canning’s reconciliation with ministers in 1814, Dent applied for a baronetcy but he was too late, as Canning, on the point of departing for Lisbon, told Huskisson: ‘How could I guess the Dog’s wish to be Sir Dogby, when he so positively denied it? Has Mrs Dog changed her mind, I wonder?’
He successfully contested Poole in 1818 and voted with government on Tierney’s censure motion, 18 May, and the blasphemous libels bill, 23 Dec., but was in the minority on the cash payments bill, 14 June 1819. He defended the method of balloting for the inquiry into Bank restriction against radical strictures, 3 Feb., and criticized Sir James Graham’s London clergy bill, 24 Mar. 1819.
During his last years, Dent was tortured by tic douloureux and he made at least one attempt to end his life by throwing himself off the cliff near his villa, but ‘it was not high enough to kill him’.