Robert and Thomas Wintour the continent and again failed to elicit Spanish support, but instead met Guy Fawkes, with whom he returned to England. Robert, a devout Catholic who inherited Huddington Court near Worcester, joined the conspiracy the following year. The plot began to unravel following the delivery of an anonymous letter to William Parker, 4th Baron Monteagle, warning him to stay away from Parliament. Thomas and Catesby confronted Monteagle's brother-in-law, the recently recruited Francis Tresham, threatening to kill him, but Tresham managed to convince them of his innocence. At that stage Thomas reportedly asked Catesby to abandon the scheme, to no avail. When
Robert and Thomas Wintour Percy, it was for the latter that the government's first arrest warrant was issued. Thomas guessed as much, and told Wright to go to Percy and "bid him begone". As the rest of those conspirators still in London fled the city, undaunted, he went over to Westminster to try and discern what he could. In author Alan Haynes's opinion, this demonstrated an impressive degree of trust in Fawkes's ability to confound his interrogators, but when Thomas heard for himself that the treason had been uncovered, he left for Huddington, stopping at his sister's house in Norbrook along the way. The