Long’s business capacity and discretion impressed Pitt, who had known him at Cambridge and who brought him into Parliament. In 1791 he became junior secretary to the Treasury under the tutelage of George Rose, foregoing all private life. Acting as whip and teller and sometimes as a publicity agent for the ministry, he was nevertheless unobtrusive; Pitt’s niece recalled: ‘Mr Long used to slide in and out, and slide here and slide there—nobody knew where he went or when he came—so quiet’. He was no orator, speaking in the House as little as possible, on business matters; as he wrote of himself to Pitt in 1801, ‘I have endeavoured to be useful—not to appear to be so’. In 1791 he was listed among opponents of the repeal of the Test Act in Scotland. In December 1792 he was to have been sent to Europe on a peace mission, but events overtook it. In 1795, in his pamphlet The new era of the French revolution, he answered advocates of a speedy peace. Apart from introducing measures to double the penny post, 25 Feb. 1794, and to limit franking, 6 Mar. 1795, he spoke at length in that Parliament only in vindication of government’s contracting the public loan through Walter Boyd, with whom Long had conducted the correspondence, 29 Feb. 1796. It was he who supplied Boyd with £40,000 from the naval funds, on Dundas’s orders, 9 Sept. Despite his family’s City connexions, he found no great favour there.
Much of the management of the election of 1796 for the Treasury devolved on Long, owing to his colleague Rose’s absence in the country: their relations were cool and ended in mutual dislike. To William Windham he wrote, 27 May, ‘I think I can promise even a better House of Commons than the last’. He himself was returned by Pitt’s friend Lord Carrington, despite a plan for John Robinson I to return him for Harwich.
In truth, without being in debt, my income is not larger, exclusive of my official salary, than when I was first appointed to the office I now hold. It is true that I might have saved something since I have been in that situation, but I am not aware that I could have saved anything material, and I believe I ought also to confess that I have yet something to learn on the score of economy. Mrs Long’s fortune and mine amount to about £1,700 a year, to which, if any circumstances should reduce us, I should not represent it as a case of distress but as one which would oblige us to do that which with the best philosophy in the world is not pleasant—to alter entirely our manner of life.
He hinted at a pension of £1,200 p.a., with half in reversion to his wife, for his ten years’ ‘laborious’ service. His own income was derived from the £20,000 left him by his father and he kept up a handsome establishment on it at Bromley Hill, as well as being an art collector. He contributed £500 towards the settlement of Pitt’s debts in 1801, helped raise more, and provided a hearth for Pitt out of office.
Long would not allow Addington to retain his services, though at Pitt’s request he remained in office until April 1801. He offered Addington a plan, which was adopted, ‘for a separation of the duties of the two secretaries [to the Treasury] and for obtaining assistance from the permanent attendance of one of the lords instead of making cyphers of them all’. When he handed over to Vansittart, The Times commented: ‘There is no one who ever had business at that office but will regret Mr Long’s resignation of it’. In June he sold his town house. For Pitt’s sake he was prepared to advise Addington on Treasury matters and accepted a privy councillorship in January 1802. At the same time he was prepared to heal their differences. As one of the ‘old school’, he thought Addington a bad election manager. He went to Paris and reported that the French detested Buonaparte. According to Canning, 6 Dec. 1802, he had not sat through any debate since Parliament met. He took no part in debate. In March and April 1803 he was chief intermediary in negotiations between Addington and Pitt for a merger, which took place at his house at Bromley Hill. Sensitive to City opinion, he warned Pitt against insisting on Lord Grenville’s inclusion. After the rupture of the negotiations, he adhered to Pitt, supplying much of the material for the pamphlet directed by Thomas Peregrine Courtenay against Addington.
On Pitt’s return to power in 1804, Long moved the writ for his re-election, 10 May. At his own wish, he was placed at the Treasury board (he was to be ‘the busy lord’). He and Rose had compiled a survey of the House which showed Pitt the need for a more comprehensive administration than the one he had opted for; in September they compiled another which pointed the same way, without even allowing for accidents such as the one that caused Rose, if not Long (who was teller), to be shut out of the division on the additional force bill on 8 June. Long, with Tierney, was an intermediary in Pitt’s efforts to reconcile the King and his heir in September 1804. He recommended and welcomed Pitt’s short-lived reconciliation with Addington, provided the latter was not given too much scope at cabinet level. Although he voted against the opposition censure of Melville, 8 Apr. 1805, he did not mind its success. In the summer he still hoped that Pitt would come to terms with the opposition.
In September 1805 Pitt persuaded Long, against his better judgment, to become Irish secretary. The viceroy Lord Hardwicke had urged this on Pitt, 9 July 1804, thinking him ‘extremely well qualified’, despite a letter from his half-brother Charles Philip Yorke suggesting that Long would do well in some respects, ‘but not in Parliament’. Long had indeed warmed to no subject in debate except the Townley marbles since Pitt’s return to office. He had already stated his reservations about Ireland to his friend Lord Redesdale in September 1804. He thought he could be more useful to Pitt at home, relieving him of Treasury business, and suggested William Sturges Bourne for the Irish post, but he was overruled. Hardwicke was delighted, hoping to leave Ireland soon after Long’s arrival, and Wickham, a predecessor of Long’s in the office, thought his appointment augured well as ‘Ireland never could be well governed without a secretary the personal and really confidential friend of the minister, and known to be such’.
On arrival at Dublin, Long found the viceroy’s confidence sapped by the pretensions of John Foster, whom he brought to book, but with such difficulty that he wondered whether it would not be better to ditch him. He wished to see the Irish secretary first lord of the Irish treasury in future, to avoid such problems. He was disappointed by Lord Camden’s refusal to replace Hardwicke. His chief task, as he saw it, was to force the consideration of Irish questions on a preoccupied English government; but he also saw scope for reforms in the police and revenue departments in Ireland. On Pitt’s death, John King informed his successor, Lord Grenville: ‘He has made such a commencement towards bringing some of the affairs of Ireland in order that it is 10,000 pities he should relinquish his post if it can be avoided. I suppose it cannot.’
Long put himself out of the question by declining to serve the Grenville ministry at the Treasury board, from loyalty to Pitt’s friends out of office. George Rose was somewhat piqued that Long was ‘singled out from all Pitt’s connexions for such a mark of favour’ as Grenville’s offer. Long disliked the inclusion of Lord Sidmouth. Even after he had refused, he might have become chancellor of the Irish exchequer. He declined through Lord Bathurst, who had also been given the opportunity to remain in office.
When at length Canning began negotiations with Grenville for a merger in March 1807, suggesting for Long a place at the Treasury board, about which there were difficulties, Long was ready for an offensive against the ministry, except on the slave trade abolition, to which he had become ‘friendly’. He voted against them on the Hampshire petition on 13 Feb. Their plan of finance provoked him to produce one of his own, ‘a plan for five years ... with no taxes for the three first, and less than £400,000 in the two last—and not touching the sinking fund, and not pledging more than £5,000,000 of the war taxes’. He broached it in debate, 16 Feb. 1807. He took office in the Portland ministry, as joint paymaster-general. He was one of the ‘men of business’ who stipulated for Sidmouth’s exclusion from office. He undertook to deputize in the House for the absent Irish secretary, Sir Arthur Wellesley, with whom he had corresponded on Irish elections in 1807, but would not consider resuming that office. He also refused the Board of Control, claiming that he had lost his political appetite since Pitt’s death. He brought in a bill to rationalize the accounting of his department, 29 Apr. 1808. Loyalty to Pitt made him the leading (and best informed) opponent, for the next five years, of the claims of John Palmer to compensation for his Post Office services. He was also a spokesman for the Chelsea Hospital directors. An attempt to drag him into the charges of corruption against the Duke of York failed, 9 Feb., 14 Mar. 1809, and he advocated their dismissal. He was dismayed at the lack of ministerial management in the House. He was, however, reported favourable to Curwen’s reform bill in May 1809.
On the break-up of the Portland ministry in September 1809, Long’s first inclination was to resign and support the King’s choice of ministers out of office. This led to the supposition that he was following Canning. In fact, while an admirer of his talents, he was critical of Canning’s conduct, seeing no future in a ministry headed either by Canning or Perceval without external aid and thinking preferable a ministry in which both served under a figurehead peer. He refused Perceval’s offer of the chancellorship of the Exchequer, for which he was not the first choice, and even the secretaryship at war, which he would have liked. He ‘never felt either disposed or fit for a cabinet office, and it would be to degrade the office to take it on any other terms’. He offered to follow his patron’s lead and Lonsdale’s preference for Perceval influenced him. The opposition leaders’ refusal to join Perceval clinched matters: Long ‘after vacillating for some time, at length agreed with himself to keep his place’. To Lonsdale he wrote ‘few persons have quitted an office with more reluctance than I retain mine’. Never intimate with Perceval, whom he thought ‘hard as iron’, Long was soon acting as muster master, calculator and teller for the ministry, as of old. The Whigs listed him ‘against the Opposition’. On 30 May 1810 his pension came under attack; he opposed the abolition of sinecures, being named to the select committee on them. He had also opposed criminal law reform and parliamentary reform, 1 and 21 May. Over the Regency bill he managed the Commons’ conferences with the Lords. By then he was convinced of Perceval’s ‘superior merits’ and preferred even Sidmouth to Canning as a recruit for the ministry. He dissented from the report of the bullion committee, 9 May 1811. He opposed the campaign against sinecures in the session of 1812, in which his own office came under attack (4 May), as having been recommended for regulation by the committee of 1810. On 21 May 1812 he was in the government minority, which he had expected to be a majority, against a remodelling of the ministry: though he was prepared to take in Canning, despite the latter’s suspicions to the contrary. Had Canning and Wellesley formed a government, he would probably have been retained where he was. Nor did he seek higher office for himself.
Long calculated a gain for ministers of 29 in the election of 1812; nor did he remember an election where popular contests went so much in favour of the government. He made light of the surprise contest for Haslemere.