He was committed to the Fleet Prison in March 1627, by warrant signed only by the attorney-general, for having refused to subscribe to the forced loan of that year.
Application for a habeas corpus having been made on his behalf, the writ was issued returnable on 8 November 1627.
Meanwhile, a warrant for Darnell's detention had been signed by two privy councillors, in which, however, no ground for confinement was alleged except the special command of the king.
Darnell was represented by Serjeant-at-law John Bramston, but asked for time to consider his new position, which being granted, he was remanded.
On 22 November Chief-justice Nicholas Hyde gave judgment, in which his colleagues John Doddridge, Jones, and James Whitelocke concurred, to the effect that the returns to the writs were sufficient.