After a siege of seventeen days the garrison surrendered "at mercy", Ford and Sir Edward Bishop presenting themselves to Sir William Waller on 6 January 1643–4 as hostages for the delivery of the castle, both thus becoming his prisoners for the second time. They were declared by parliament on 9 October 1644 to be incapable of any employment. Ford was imprisoned in the Tower of London, from which in December he escaped. He then retired to the continent. In 1647 the queen, knowing his relationship with Ireton, sent him to England to join Sir John Berkeley in a futile negotiation with the army. On 12 November 1647 Ford with others was ordered by the House of Commons into safe custody upon suspicion of being privy to the king's escape from Hampton Court. On 21 March 1648/9 parliament ordered that he should pay for his delinquency one full third of the value of his estate. On 9 July 1649 the house made an order for remitting the remainder of his fine and discharging his sequestration. In 1656 Ford was employed, with Oliver Cromwell's encouragement, and at the request of the citizens of London, in devising an engine for raising the River Thames water into all the higher streets of the city, a height of ninety-three feet. This he accomplished in a year's time, and at his own expense; and the same "rare engine" was later employed for draining mines and lands. He later, with Thomas Toogood, constructed the water-engine near the Strand Bridge for the neighbourhood. As it obstructed the view from Somerset House, Catherine of Braganza caused it to be demolished; but Ford and Toogood obtained a royal licence to erect other waterworks at Wapping, Marylebone, and between Temple Bar and Charing Cross. After the Restoration he invented a mode of coining farthings. Each piece was to differ minutely from another to prevent forgery. He failed in procuring a patent for these in England, but obtained one for Ireland. Ford died in Ireland before he could carry out his plans for coins, on 3 September 1670. His body was brought to England, and interred in the family burial-place at Harting. Works Ford wrote: A Design for bringing a Navigable River from Rickmansworth in Hartfordshire to St. Giles's in the Fields, London, 1641, with an answer by Sir Walter Roberts, printed the same year, and both reprinted in 1720. Ford's pamphlet