Alexander’s uncle the nabob James Alexander, after sitting for Londonderry in the Irish parliament, became Lord Caledon. He returned his ambitious young barrister nephew for Newtownards (1788-90), Askeaton (1790-7) and Londonderry city (1797-1800). Alexander steadily supported government and became chairman of supply with £500 p.a. in 1798, though he wrote, ‘Income I never cared about, except to guard against contested elections’. Disillusioned by the Irish rebellion, he informed his friend the chief secretary, Thomas Pelham, 26 Sept. 1798, ‘if I cannot enter into a military line of life, I certainly will devote my whole time to official duties and political investigation and labour’. He added that he thought Lord Cornwallis’s system the only one that could save the country but wished it to be better understood and more honestly explained and justified. Soon afterwards he assured Pelham, while asking for a bishopric for his brother, ‘I believe no class of men in Ireland have devoted [more] of their time, labour and property to the service of government than my family. I claim some little merit as having been the first man who ventured boldly to declare in Parliament the effort I saw to separate these kingdoms.’
Alexander was returned to Westminster for Derry in 1801, and after making himself useful to government that session in Irish debates by defending their coercive measures, legal arrangements and indirect taxes, became in November, as a compliment to Ireland, chairman of committees in the Imperial Parliament. Isaac Corry’s comment was, ‘Everybody is surprised, but none of the Irish displeased as far as I hear’. Alexander would not have obtained the appointment, worth £1,200 p.a., if Addington’s negotiation with Charles Grey had succeeded, but would possibly have been a third secretary of the Irish treasury instead. He was a busybody who irritated Abbot, then chief secretary, by taking it upon himself to win Pelham at the Home Office round to Abbot’s Irish reforms, and by giving despondent accounts of the discontent of the Irish Members about them, suggesting that Abbot needed a confidential agent among them to keep them right.
Whatever his shortcomings as chairman, Alexander continued to intervene regularly in debate on Irish questions and sometimes on others, such as the extension of the Bankruptcy Laws, which he opposed, 23 Feb., and Burdett’s censure of Pitt’s wartime government which he rebuked, 12 Apr. 1802. He had already decided to cede Derry to Sir George Hill at the next election and came in instead for his cousin Caledon’s borough of Old Sarum; but having no constituents there, he continued to be an Irish Member in his preoccupations. Excluded from Derry, he preached to the Irish secretary by the hour on the county patronage, ‘pressing for a portion of it for himself exclusively’.
Alexander had an interest in banking in Derry and took part, as a member of the select committee, in the Irish currency debates, 13 Feb., 2 Mar. 1804 and 21 Mar. 1805. He also opposed the exemption of the Irish linen trade from duties, 3, 9 Mar. 1804, in view of its prosperity. He deprecated the censure motion on the lord lieutenant, 7 Mar., and defended the volunteer consolidation bill, 19 Mar., the Irish militia offer bill, 10, 11, Apr. and the Irish militia augmentation bill, 16 Apr., marking his hostility to the combination of old and new oppositions. He went on to support Pitt’s second ministry (except allegedly on 11 June 1804) and supported the suspension of habeas corpus in Ireland, 8 Feb. 1805. He opposed the Catholic claims at some length, 13 May 1805. He was in the government minority against the censure of Melville, 8 Apr., and pronounced in favour of prosecution by the attorney-general rather than impeachment, 25 Apr., 11 June 1805. On 7 June he was government teller for the Duke of Atholl’s claims.
That autumn Alexander was out of humour with the viceroy Hardwicke, to whom he was described by the Irish lord chancellor as ‘hostile’: his kinsman Alderman William Alexander of Dublin had fallen foul of the viceroy over municipal politics. Alexander acted as mediator with the chief secretary Long, who evidently thought he pitched the claims of his family on government too high. Alexander blamed the viceroy’s impressions of his and his family’s hostility on the under-secretary Marsden’s ‘misrepresentations’ and, so he informed Caledon, ‘I stated I hoped his mind was too large to consider our bye battles for local and personal objects connected with any hostile efforts essential to the great leading features of the country’. He concluded by proposing that if Hill vacated Derry, he should replace him and bestow Old Sarum on Castlereagh.
After sounding Fox in the House, 18 Feb. 1806, as to his views on the Union, Alexander was satisfied and went on to support the Grenville ministry, voting with them for the repeal of the Additional Force Act, 30 Apr. Paying tribute to the Irish chancellor of the Exchequer on his budget, 8 May, he found fault, however, with Newport’s Irish election bill, designed to reform corporations, which would damage the protestant interest, 19 June, and likewise with Newport’s ‘new and partial’ Irish poor relief bill, 26 June. On 2 July Caledon was appointed governor of the Cape and Alexander was reported to be going with him as secretary.