Thomas Osborne, 4th Duke of Leeds, KG, PC, DL, FRS (6 November 1713 – 23 March 1789),[1] styled Earl of Danby from birth until 1729 and subsequently Marquess of Carmarthen until 1731, was a British peer, politician and judge.

[4] Osborne received a Doctorate of Civil Law in 1738[3] and became a Fellow of the Royal Society a year later.

[5] Osborne became a Lord of the Bedchamber in 1748 and was appointed Justice in Eyre south of Trent in November of the same year.

[6] In June 1749, he was made a Knight of the Order of the Garter and in 1756, resigning from his post as justice, was nominated Cofferer of the Household.

[7] He was sworn of the Privy Council of Great Britain a year later and became Justice in Eyre north of Trent in 1761, an office he held until 1774.