Carmarthen’s father, who was summoned to the Lords in his mother’s barony of Conyers in 1798 and succeeded as 6th duke of Leeds the following year, took little active part in politics, but he abandoned his father’s Foxite allegiance and went over to Pitt; his younger brother, Lord Francis Godolphin Osborne*, remained true to Whig principles. Leeds was a favoured crony and trusty drinking companion of George IV, and was sometimes the worse for wear in public: in March 1828, according to Thomas Creevey*, he and the king ‘got so drunk as to be nearly speechless’, and the following year Lady Granville encountered him in the royal entourage at Ascot races, ‘drunk as a fish [and] quite incoherent’, though she observed that ‘scarlet strawberries in private conversation are very agreeable to meet with occasionally’.
At the general election of 1826 Carmarthen had been returned for Helston on his father’s controlling interest, and he subsequently received a formal request for attendance from Canning, the leader of the Commons in Lord Liverpool’s ministry.
Carmarthen, who subsequently gravitated towards the Whigs, succeeded to the dukedom in July 1838, only eight days after being summoned to the Lords in his father’s barony of Osborne. He inherited the settled family estates at Hornby Castle, near Bedale, Yorkshire, and in Cornwall. However, other real estate and the bulk of the personalty, which was sworn under £60,000, went to his brother-in-law, Sackville Walter Lane Fox*, whom the old duke had evidently treated almost as a son.
