By birth a Yorkshire, and by marriage a Welsh, country gentleman, Cook entered the army on the same day and in the same regiment as the Hon. George Fitzwilliam, Earl Fitzwilliam’s younger brother. His local military activities would have strengthened his connexions with Fitzwilliam, whose borough he represented and whose political line he followed.
He was briefly out of the House after a local revolt of Fitzwilliam’s tenantry at Malton in 1807, but was again elected after a successful petition and a contested by-election. He continued to vote with the Whigs in the sessions of 1809 and 1810 in a pattern similar to that of Fitzwilliam’s son, Viscount Milton, although unlike him he voted in all divisions against the Duke of York, 15 and 17 Mar. 1809. His last recorded vote was against the adjournment, 29 Nov. 1810. On 31 Dec. he took two weeks’ sick leave. On 7 Jan. 1811 he informed Fitzwilliam that he regretted his inability to attend and vote against the Regency restrictions. On 3 Feb. he wrote again, still not recovered, and lamented that the ‘states of the realm’ appeared to be as mad as the King and unfit to extricate the country from its difficulties.
