dying very early, left his widow in poverty. Knighton, after a little schooling at Newton Bushell, Devonshire, was at an early age sent to study medicine under his uncle, Dr. Bredall, a surgeon of Tavistock. He afterwards studied for two years at Guy's Hospital, London. At the age of twenty-one he returned to Devonshire, and obtained through the influence of Dr. Geach, chief surgeon of the Royal Naval Hospital at Plymouth, an assistant-surgeon's post there, and a diploma from St. Andrews University. At the end of 1797 he settled in practice at Devonport. In 1800 he married Dorothea, youngest daughter of Captain Hawker, R.N., and in 1803 he removed to London. He began practice as an accoucheur, but shortly removed to Edinburgh. After three years' study there, he once more returned to London, received a degree from the Archbishop of Canterbury, and the degree of M.D. from the university of Aberdeen (21 April 1806), and began practice in Hanover Square. In July 1809 he attended the Marquis Wellesley as his physician on his embassy to Spain, and returned with him in October. By him he was in 1810 recommended to the Prince of Wales, with the result that he became one of the prince's physicians, and was shortly afterwards created a baronet (1812). The prince told Sir Walter Farquhar, in explanation of this appointment, that Knighton was the best-mannered doctor he had ever met. He had been an intimate friend of Sir John Macmahon, and when, on the latter's death in 1818, he came, as executor, into possession of some of his papers, which were compromising to the prince, he at once delivered them up, conduct which so charmed the regent that he appointed him to the auditorship of the duchy of Cornwall and of the duchy of Lancaster, and soon began more and more to consult him on matters of business.
Knighton's firmness of character appeared in his management of George IV's inextricably confused affairs. In spite of the king's extravagance, Knighton gradually reduced his finances to order, caused the debts to be steadily liquidated, and asserted over the king's weak mind an authority which few of the ministers enjoyed (cf. Lord Ellenborough, Diary, i. 384; Greville Memoirs, 1st ser. i. 100, 144; Lord Colchester, Diary). The king wrote to him as ‘dearest friend,’ signed himself ‘most affectionately yours,’ and gave him written authority to notify the royal tradesmen that no goods were to be supplied or work done on account of the privy purse except upon Knighton's orders given in writing. Knighton had attended him on the continent in 1821, and received the degree of M.D. from the university of Göttingen, and on the return of the court to England he was appointed private secretary to the king and keeper of the privy purse, in succession to Sir Benjamin Bloomfield. He thereupon gave up practice on 11 Sept. 1822. He was frequently employed on confidential missions for the king both at home and abroad, but their precise nature is unknown, as all his letters on the subject were destroyed by his widow. He was sent to Paris in 1823, and in 1824 made three journeys in rapid succession to Paris, Spain, and Sardinia. ‘At a moment's notice,’ he writes to his wife, ‘the king has again ordered me abroad … my situation involves very heavy penalties on me.’ These sudden and toilsome journeys, continued yearly and often several times a year till 1825 and 1826, probably contributed to bring on the severe illness which overtook him in 1827. He was highly esteemed by the royal family and by the ministry, having taken to heart the Duke of Wellington's advice to beware how he interfered in politics; but he became the object of considerable ill-will, owing to his undoubted influence with the king (see Lord Colchester, Diary, iii. 527, 539; Raikes, Diary, iii. 53, 54). A severe attack was made upon him by T. S. Duncombe in his maiden speech in the House of Commons on 18 Feb. 1828; but Peel met it by a point-blank denial (Hansard, Parl. Debates, 2nd ser. xviii. 540). The attack appears to have been got up as a joke by Henry de Ros and Charles Greville (see Greville Memoirs, 1st ser. i. 128); but to Knighton, who was then abroad and unable to defend himself, it was very painful. He attended the king almost night and day during his last illness, was present even at political interviews in the royal closet, and appears not only to have been sincerely attached to the king, but also to have esteemed him. His vigilance prevented Lady Conyngham from profiting by the temporary disorder at Windsor during the king's illness to lay hands on any of the royal jewels, and after the king's death on 26 Jan. 1830 Knighton was busily occupied for several months in winding up his affairs. He subsequently gave up his house in London and retired into the country, which suited his failing health better than town. He died, however, in Stratford Place, Oxford Street, London, on 11 Oct. 1836 of an enlargement of the heart, and was buried at Kensal Green cemetery.
He had considerable taste, especially in painting, very great social tact, a sound business capacity, and honestly fulfilled the duties of a very delicate position. Though he long held a position where his court interest might have commanded almost any favour, he proved