Pratt, John Jeffreys (1759–1840), 2nd Earl Camden , lord lieutenant of Ireland, was born 11 February 1759 in London, the only surviving son of Charles Pratt, later 1st Earl Camden, and Elizabeth Pratt (née Jeffreys). Educated at Fawley, Buckinghamshire, and at Trinity College, Cambridge, he graduated MA (1779). Entering parliament as MP for Bath (1780–94), he displayed little interest in politics, and his maiden speech on 12 June 1781 was not a success. Modest and diffident, he was appointed a teller of the exchequer in May 1780, a lucrative sinecure that was worth £23,000 a year by 1807. A lord of the admiralty on two occasions (1782–3, 1783–9), and also a lord of the treasury (1789–94), he benefited greatly from the patronage of his friend William Pitt, prime minister 1783–1801. Styled Viscount Bayham (1786–94), he succeeded his father as 2nd Earl Camden on 18 April 1794. In June 1793 Pitt first proposed the idea of his going to Ireland as lord lieutenant, but Camden vacillated over the invitation. With the recall of Earl Fitzwilliam (qv) in 1795, Pitt wanted someone he could trust completely. Camden reluctantly accepted the responsibility and was appointed lord lieutenant on 13 March. On his arrival in Dublin (31 May) there was a riot when his carriage reached Dublin Castle, the army attempted to restore order, and two people were killed. With Thomas Pelham (qv) as his chief secretary, Camden worked to restore the authority of the Castle. In a conciliatory gesture to the catholics, one of his first actions was the introduction of the bill to establish Maynooth College. Although Camden was inclined to pursue conciliatory policies, he submitted to the direction of hardliners such as John Foster (qv), John Fitzgibbon (qv), and John Beresford (qv) and his administration soon became notable for its coercive strategy; habeas corpus was suspended and the army embarked on a ruthless campaign to crush disaffection.
By 1798 Ireland was on the brink of open insurrection and Camden proved increasingly incapable of controlling the crisis. In March he repeated the request first made in 1796 and asked that his stepnephew Robert Stewart (qv), Viscount Castlereagh, should be appointed acting chief secretary in place of Pelham, whose health was failing. The government acquiesced, although with much reluctance. By this time Camden had realised that he lacked the abilities to be a successful lord lieutenant and he urged Pitt to appoint someone who could unite the offices of commander-in-chief and viceroy. Dominated by a small clique of advisors who repeatedly urged extreme and repressive measures, Camden exacerbated the crisis with his actions and made violence inevitable. On the night of 23 May 1798 the rebellion finally began, and on hearing the news the immediate reaction of Pitt was to press for a legislative union and replace the lord lieutenant. Pitt urged Camden to control the violence of his cabinet, as much as that of the rebels, and moved to replace him with Marquess Cornwallis (qv). The speed of the change upset Camden when he was informed of Cornwallis's appointment on 15 June, and he later regretted that he had not been allowed to oversee the union. But a key factor against his continuance in office was his opposition to catholic emancipation; he was, as he had admitted to his nephew ‘a very prejudiced Englishman’.
Returning to London, he sat in cabinet as a minister without portfolio, and became a KG. With the passing of the union he sided with Pitt on the question of catholic emancipation in 1801, out of friendship rather than conviction, and resigned along with the other ministers when it was vetoed by the king. He returned to government as secretary of state for war and the colonies (1804–5), but refused Pitt's request to return to Ireland as lord lieutenant in 1805. He was also lord president of the council (1805–6, 1807–12). On 7 September 1812 he was created Marquess Camden in recognition of his services.
He died 8 October 1840 at his estate at Kent. He married (31 December 1785) Frances Molesworth; they had one son and three daughters.