Falkland had for some years been engaged in tracking out what he supposed was a dangerous conspiracy of the Byrnes of Wicklow, and in August 1628 was able to announce to Charles I that the result of his protracted investigations had been successful, a true bill having been found against them at the Wicklow assizes. The aim of Falkland was to set up a plantation in Wicklow on the confiscated estates of the Byrnes, but as his designs were disapproved of by the commissioners of Irish causes, the king appointed a committee of the Irish privy council to investigate the matter more fully. Falkland took deep offence because one of the members of committee was the lord chancellor, Loftus and he refused to afford any assistance in the investigation on account of the "high indignity" offered to himself. When, as the result of the inquiry, it was discovered that the Byrnes had been the victims of false witnesses, Falkland was, on 10 August 1629, directed to hand over his authority to the lords justices on the pretext that his services were required in England. Charles I, recognising his good intentions, continued him in favour.