As soon as he was of age to do so, Lord Brooke came in for Warwick on the family interest and held the seat unopposed until he succeeded to the title. Having gone to Russia in 1801, he was absent on the Continent until August 1803. Caroline Fox, Lord Holland’s sister, who had a soft spot for him despite his lack of ‘brilliant abilities’, remarked: ‘It was lucky he sailed when he did for Constantinople or he might have been detained with others of his countrymen in Italy’.
Brooke was badly off and hoped to marry the heiress of Sir George Shuckburgh Evelyn in 1807, but Lady Harriet Cavendish saw his chief disadvantage: ‘Lord Brooke, whose very look is bore, indefatigable bore and whose "tongue keeps good the promise of his face"’. Apparently, when he began a story, ’he went on working it up till there was nothing for it but to pretend to go into a fit, for nothing short of that would satisfy him as to the degree of astonishment and interest he wished to excite in his hearers’.
Brooke supported the Portland and Perceval ministries silently, but he declined a place at the Treasury board offered by the latter in November 1809.
