Ponsonby’s political pedigree was impeccable. Born into the consanguineous inner circle of leading Whigs, his uncle was Lord Duncannon, ‘the great manager’ of Brooks’s, whose daughter he later married in a ‘love-match’, according to family legend having worn down his reluctant uncle, who was concerned at their common ancestry, by standing outside Duncannon’s chambers when he took his morning bath and shouting, ‘Hi, Hi, I want to marry Maria!’
Re-elected for Poole after a severe contest in 1841, when present he sided with the Whig opposition to the Peel ministry on a number of key issues, including the introduction of income tax, 18 Apr. 1842, the ecclesiastical courts bill, 28 Apr. 1843, agricultural distress, 13 Mar. 1845, and the Irish coercion bill, 1 May 1846, and was probably the ‘Mr. Ponsonby’ who brought up petitions against the factories bill, 28 Apr. and 29 May 1843. In his only known speech, 21 June 1842, he contended that ‘the ballot would be found an effectual cure for the prevalent sin of bribery’ and ‘knock it on the head at once’. A consistent supporter of free trade, for which he cast minority votes, 11 Mar. 1842, 26 June 1844, he divided for the third reading of Peel’s controversial bill to repeal the corn laws, 16 May 1846, and duly rallied behind the incoming Russell ministry next month.
That year Ponsonby helped expedite the sale of the family estate at Canford, held in trust for the equal benefit of himself, his younger brother Ashley George John Ponsonby and his brother-in-law Lord Kinnaird, by assisting its transfer to the Guests, who eventually paid £335,000, rather than putting it up for public auction and reassuring his procrastinating father (since 1838 Baron de Mauley). If the Guests were grateful, it did not extend to supporting him at the 1847 general election (as de Mauley had hoped), and Ponsonby instead came forward for the Irish constituency of Youghal as the nominee of his father’s first cousin, the 6th duke of Devonshire.
although a supporter of the general policy of the government, I cannot but view with regret the reimposition of the income tax in its present oppressive form, and hope that before long property will bear its fair share of the national burdens, and that by strict economy the industrious classes will be relieved of a tax which presses so unequally upon them.
The Times, 22 May 1848.
He was soundly beaten by a Protectionist Tory, but with the assistance of Devonshire, whose guest he was at Chatsworth in September 1848, he eventually secured a temporary berth at Dungarvan in March 1851, after a controversial by-election delayed with ministerial collusion until the newly lowered Irish voting qualifications had come into play.
Ponsonby succeeded to his father’s barony in 1855 and when present in the Lords continued to support the Liberals. Alarmed at the increasing size of that chamber’s membership, one of his last known acts was to unsuccessfully propose that peers be allowed to stand for election to the Commons and be excused attendance in the Lords.