Smyth was successful for the third time in the contest for Pontefract in 1790 and this time his championship of the householder franchise against the burgage holders was vindicated by decision of the House; but his seat was not thereby rendered secure. Since 1784 he had committed himself to the support of Pitt’s administration and, like Pitt, proceeded to lose interest in parliamentary reform. On 14 Dec. 1790 he defended the convention with Spain in debate. In March 1791 report had it that he would be appointed comptroller of the Household. Not so, but in June, Pitt, commending him to the King as ‘likely to be efficient and useful in business’, placed him at the Admiralty board. He survived a further contest on his re-election. Apart from a speech in opposition to the slave trade on 19 Apr. 1791 (he further voted for abolition on 15 Mar. 1796), he figured in debate only in his official capacity, and that seldom. In May 1794 he transferred to the Treasury board: ‘to an ignorant person he would have appeared to be the secretary and [George] Rose and [Charles] Long the board’.
Re-elected unopposed then and in 1796, Smyth was chairman of the Carmarthen election committee. He voted with ministers on the loyalty loan (to which he had subscribed £5,000), 1 June 1797, and for the assessed taxes, 4 Jan. 1798. He made himself useful as chairman of the committee on Pitt’s income tax bill in December 1798. (On 17 Apr. 1800 he resisted an attempt to amend it.) On 8 May 1800 he expressed his satisfaction with Pitt’s war aims: security, not the restoration of the Bourbons, though the latter was the best means to the end. At that time Pitt suggested his removal to the India Board to make way for Lord Temple at the Treasury, but he refused to move, allegedly because of ‘the inconvenience of re-election’.
Smyth was nevertheless unenthusiastic about remaining in office when Addington took over from Pitt; he doubted whether the new government would stand, and allegedly resented the rebellion of Canning against Pitt’s request to support it by remaining in office. Addington promoted him to the Mint and made him a privy councillor in 1802, after he had escaped a contest for his seat. He presented his constituents’ petition against the malt duties, 24 Dec. 1802, but otherwise figured in the House only as chairman of the Ilchester election committee, whose recommendations to prosecute delinquents he was unable to carry as he wished, 22 Apr. 1803. His allegiance to Addington seemed fixed, but the latter admitted when negotiating a possible junction with Pitt in April 1803 that Smyth was ‘accidentally placed’ where he was and might be replaced.
On 30 May 1804 Smyth wrote to Pitt:
The political connexion which I long since formed with you, has made one of the chief circumstances of happiness and pride in my life—I never have had nor can have the idea of any permanent attachment opposed to you. I accepted indeed a great favour from Mr Addington (having refused one on your quitting office) at a time when I thought it perfectly consistent with my attachment to you, and I could not depart from the obligation I had thus incurred, at a moment when it seemed certain that his administration must be overturned—others I am sure whose original attachment was to you, have acted from the same feeling; none I may say more distinctly.
... If my office is wanted in your arrangements, I must consider the forfeit of it as naturally incurred. I own ... it would be particularly painful to me, to have an end put to that connexion which I valued so very highly. Still however with every good disposition on your part, it may not be in your power to exempt my office from your new arrangements, if that cannot be, I have only to say that what has suggested itself to you respecting my son, affords an opportunity for your kindness towards me, which will be gratefully received.
Dacres Adams mss 5/36.
In compensation Pitt met Smyth’s wish that his son be appointed under-secretary to Hawkesbury with the prospect of a seat in Parliament, and Smyth in due course was made a member of the Board of Trade. He remained Pitt’s adherent (somewhat to Addington’s indignation) and voted against the censure of Melville, 8 Apr. 1805.
On Pitt’s death he was one of those who thought that the House would ‘very readily’ agree to pay his debts and met with Pitt’s friends to recommend a resolution on the subject: the one he proposed was not adopted at the meeting.