During the contest against a "token" group of independents, he was accused of trying to "forge" an "unnatural coalition" with the sitting Tory, Sir Charles Cockerell, 1st Baronet.
He also, in 1828, voted against extending the franchise of East Retford to include Bassetlaw, and supported reducing corn duties.
He also supported Lord Blandford's parliamentary reform scheme in 1829, and proposed an amendment on the "need to alleviate distress"—stating "discontent from large masses" and the "growing contempt in which the House is held" could only be reduced by a "decided retrenchment of expense, large reduction of taxation, and by a needful reform, commencing with our own House".
[8] Protheroe also presented a number of petitions to the House of Commons, including in favour of Catholic relief and emancipation; the repeal of the Test Acts; against the relocation of Smithfield cattle market, plans for which he said were "absurd and ludicrous"; against the burning of Hindu widows on behalf of women of Alcester; to complain of distress from Stow-on-the-Wold; for Jewish emancipation; for the abolition of the death penalty for forgery; and from the Forest of Dean collieries against coal duties.
He also supported several inquiries, including to probe electoral interference by Leicester corporation in 1827; obtaining detailed accounts of the work of the public records commissioners in 1828 and 1829; and to investigate chancery delays in 1828.
In the latter year, he was appointed to a committee on the borough polls bill and quizzed ministers over their intentions relating to "alteration of the Trinidad laws".
[2][4][8] He largely blamed this failure on "formidable opposition from the powerful body of the West Indian interest" and his support for the abolition of slavery.