Pratt, John (1670–1741), MP and government official, was fourth son of Joseph Pratt of Cabra Castle, Co. Cavan, and his wife Elizabeth, daughter of Sir Audley Mervyn (qv) of Co. Fermanagh. One of his brothers, Benjamin Pratt (qv), was provost of TCD, and another, Mervyn, MP for Co. Cavan 1715–27. He entered TCD, aged fourteen, in 1684, graduating with a BA (1689). On leaving university he embarked on a successful military career, becoming an adjutant in Brig.-gen. Thomas Erle's (qv) regiment of foot (1693), and later rising to the rank of captain (1703).
He entered the Irish house of commons in 1713, representing Dingle, a constituency he continued to sit for until 1727. Despite being initially regarded as a tory, he prospered following the Hanoverian succession. On 16 February 1716 he was appointed deputy vice-treasurer, receiver, and paymaster general. In his early years in office he appears to have been an efficient supplier of information to parliament, and probably was at least partly responsible for creating an effective financial system. In addition he was a useful man to the government in various capacities, for instance, he bought Hester Sherlock's decree for £1,860 (1717), thereby ending her litigation against Annesley and neutralising the dissension that had surrounded it, for the Annesley–Sherlock case had been the immediate cause for the British act of 1720, 6 George I, which prevented the Irish house of lords from acting as a final court of appeal. Also in 1717, he was appointed constable of Dublin castle, a position that brought him an income of £350 a year.
However, Pratt's position as deputy vice-treasurer, receiver, and paymaster general ultimately led to his downfall. He controlled the finances of the nation and (in keeping with contemporary practice in both Great Britain and Ireland) so long as he could produce the necessary money when required, he had the use of it in the interim. Many family fortunes were made this way, but it was a risky practice, particularly during periods of financial instability such as the early 1720s. Probably for this and domestic reasons – the death of his two sons by drowning in the Phoenix Park in 1723 and suspected estrangement from his strong-minded wife, Honoretta daughter of Sir John Brookes of York – his financial judgement was impaired. The accounts had not been regularly audited; although earlier he appears to have done this regularly, by 1725 there were discrepancies amounting to the then enormous sum of £100,000. In addition he owed his private creditors, including Jonathan Swift (qv), large sums of money. His downfall came as a surprise, as up to this date he was regarded as a ‘wary accountant’, whose lifestyle was attributable to a ‘fortunate marriage and clever investments’ (Barnard, 162). On 8 June 1725 he was committed to the Four Courts Marshalsea by order of the government, and on 19 November 1725 the public accounts committee requested the house of commons to appoint a committee to establish ‘such particulars in the accounts as shall be demanded of them’ (HIP, vi, 113). The disaster brought to the fore Luke Gardiner (qv), one of the best financiers Ireland ever produced, who managed to sort out the chaos and lay the foundations for his own and his family's fortune. On 13 May 1727 Archbishop Hugh Boulter (qv) wrote to Lord Lieutenant Carteret (qv): ‘We have spared no pressing to get Mr Pratt's affairs ended, and hope in a little time to sell his estate’ (ibid.).
Among Pratt's estates was the town of Newtown Pratt, Co. Mayo, where he had attempted to establish a protestant colony on the west coast. Pratt lost his estates but not his reputation, partly because much of the blame was rightly or wrongly attached to the treasury and the lord lieutenant, for not seeking regular accounts; the spectre of the divisions caused by the ‘Wood's halfpence’ debacle also hung over the proceedings. On his release from prison, Pratt established himself as a glass manufacturer and coal merchant in Dublin. He was also a foundation member of the Dublin Society in 1731. He died 24 March 1741, and was survived by his estranged wife and his only daughter, Mary. His wife died in 1769 aged 95, leaving instructions that her body should be burnt to avoid endangering the health of her neighbours. There is a portrait (c.1720) in family possession in Co. Mayo, which is reproduced in Malcomson's Nathaniel Clements.