In March 1596 Essex commissioned Gerard to recruit a thousand men to serve in an Anglo-Dutch expedition to Cadiz, which set off from Plymouth in June. Gerard accompanied the expedition as colonel of a regiment of foot. The Capture of Cadiz was one of the most severe losses suffered by Spain in the war, with the city itself and the Spanish fleet destroyed. Gerard was not paid for his service but he had a small ship of his own, which he used for privateering. Over the next two years, he was involved in organising militia forces in Northamptonshire, Middlesex and Hertfordshire to guard against a possible Spanish invasion. In May 1597 Gerard was honoured with the post of Knight Marshal of the Household, deputy to Essex, the Earl Marshal. In November 1597 Gerard was returned again to the House of Commons as member for Lancashire, although not before Molyneux, now High Sheriff of Lancashire, had his revenge for past slights by sending back the election writ to London on a technicality. Molyneux's position barred his standing, and Gerard's colleague this time was Robert Hesketh of Rufford Hall. Breach with Essex It was the Irish war that finally split Gerard from the Essex faction. Essex was nominated for the post of Lord Lieutenant of Ireland by the Cecil faction, in the expectation that he would fail. Gerard travelled with Essex to Ireland in April 1599 and they stayed at his Staffordshire manor of Gerrard's Bromley together on the way. They reached Dublin on 15 April but Gerard left within five days. It is not clear what his duties, if any, had been in Ireland and he did not return. The Privy Council ordered Gerard to send supplies to Ireland from the Isle of Man, but he had no further dealings with Essex in Ireland. In April 1600 he was still attending to his duties in and around London, conducting the French ambassador to the coast to meet messengers from Henry IV, and keeping in close touch with Cecil. When Essex returned to disgrace in May, Gerard left the court and headed for the country. It seems he had been accused of something, perhaps concerning his dealings with Essex, by Roger Manners, 5th Earl of Rutland, a strong supporter of Essex. Gerard wrote to Robert Cecil on 9 May in abject terms, seeking to explain his actions, although he had clearly panicked: