The Times had been against his election, disparagingly describing him as "a mere practitioner in the courts"[4] adding that he lacked the personal dignity and legal ability required for the role.
Knowlys was forced to resign in 1833 after issuing a warrant for the execution for Job Cox, a postman in the service of the General Post Office who was charged with stealing the contents of a letter entrusted to him for delivery.
Resolved unanimously, that this Common Hall has learned, with feelings of the deepest horror and regret, that the life of Job Cox, a convict under sentence of death in Newgate, had well-nigh been sacrificed by the act of the Recorder of London in sending down a warrant for his execution, notwithstanding his Majesty in Privy Council had, in the gracious exercise of his Royal Prerogative of mercy, been pleased to commute his sentence for an inferior punishment.
Resolved unanimously, that the mildest and most charitable construction which this Common Hall can put upon this conduct of the Recorder is that it was the result of some mental infirmity incident to his advanced age; but contemplating with alarm the dreadful consequences which, though happily averted in the present instance, may possibly ensue from such an infirmity in that important public functionary, this Common Hall feels that an imperative duty to record the solemn expression of its opinion that the recorder ought forthwith to retire from an office the vitally important duties of which he is, from whatever cause, incompetent to discharge."
[2] Newman Knowlys died on 5 January 1836 at his house in James Street, Buckingham Gate, London, and was buried in the vault of the Middle Temple.