Cholmeley initially had no intention of contesting the Grantham seat that his father had vacated at the 1826 dissolution. Two candidates had declared, but an expected third man had failed to appear by the eve of the election, when Cholmeley impulsively threw his hat into the ring, ‘being convinced that a body of some 800 freemen would never be voluntarily deprived of the privilege of a choice’, and hoping ‘that the lateness of the application will not be wrested to my disadvantage’. On the hustings he added that his late mother had believed that ‘obtaining a seat in the House of Commons’ was the ‘greatest honour to which his ambition could be raised’, and noted ‘how much greater’ it would be as the ‘representative of his native borough’. Pressed for his views during the poll, he quashed rumours that he was a supporter of Catholic emancipation, observing that although they had a ‘theoretical justice in their complaint’ he had ‘very great doubts on the practical expediency of granting them the concessions they demand’, and promised to ‘bow to the decision’ of his constituents on the issue. He was returned in second place. At the declaration he denied claims that he was a Whig and had ‘no opinion of his own’, saying ‘the best refutation of that idea was his coming forward on his own opinion, when it was in opposition to that of his father ... for whom he entertained the highest regard’.
Cholmeley was granted two months’ leave on account of being abroad, 6 Mar. 1827. There is no known trace of parliamentary activity until 25 Apr. 1828, when he presented a petition against Catholic claims, observing:
This purports to come from the burgesses of Grantham; but it would a libel on very many respectable members of that body, if I said it came from the whole ... Though I am also hostile to the prayer of the petition, I am glad it has been presented ... for it is a fact that though great exertions have been made to procure signatures ... they have for the most part been unsuccessful. This shows that the more the question is discussed, the more will it be found to gain in the public estimation. We shall, I have no doubt, soon see a general disposition in the country to admit all classes ... to an equal participation of rights and privileges.
He voted for relief, 12 May. He divided against the provision for Canning’s family, 13 May, and the bill to restrict the circulation of small bank notes in Scotland and Ireland, 5, 16 June, and brought up a Grantham petition against the controls on £1 notes next day. He voted against the appointment of a registrar to the archbishop of Canterbury, 16 June, and the use of public funds for Buckingham House, 23 June (as a pair).
On 14 Feb. 1829 he joined Brooks’s, sponsored by Lords Fitzwilliam and Duncannon*. That month Planta, the Wellington ministry’s patronage secretary, predicted that he would vote ‘with government’ for their concession of Catholic emancipation, but he cast no known votes on the measure. He divided for a reduction of hemp duties, 1 June, was one of those shut out of the division on Lord Blandford’s reform scheme, 2 June, but later that day was in the minority of 44 for the issue of a new writ for East Retford. On 29 June 1829 he defended the bishop of Lincoln, who had been criticized by Hume in relation to pluralities, insisting that ‘no prelate has given such great satisfaction’ and noting that ‘in some places the benefices’ involved were as ‘small as £20 a year’. At a Lincolnshire county meeting, 8 Jan. 1830, he doubted the alleged levels of distress, particularly since the ‘government acted on the principle of giving relief to the greatest clamourists’, but agreed that repeal of the malt and beer duties would be useful, though ‘it would be as a drop in the ocean’.
He duly retired, having assured his brother-in-law Glynn Earle Welby*, who started for the vacancy, that he would not stand. Following a series of deputations from the freemen, however, he rejected an invitation to contest Lincoln, which his father had given ‘every reason to expect’ that he would accept, and agreed to come forward again.
I told you I would not be a party man, and I assure you, that I am now more fixed in this determination. I have seen sufficient to deter me from identifying with any party ... I have seen parties broken up, and I hope they will be more broken up in the next Parliament, for I do not think the present ministers, as far as they can, consult the people’s interest.
Heckled by his opponents, he denied breaking a ‘pledge’ not to stand and ridiculed objections that he owned not even ‘one pigsty’ in the town, asking ‘how could he monopolise the interests of the borough’, as alleged, if he had ‘no other hold upon them but their good opinion?’ He was returned in second place behind Welby. At the county election he nominated the independent Whig Sir William Amcotts Ingilby*. A few weeks later he subscribed £25 to the Stamford fund for purity of elections.
He declined to contest the ensuing general election, citing his father’s death and an ‘unfortunate illness’ induced, he believed, by that event and ‘his attendance in Parliament on the late all important bill’, which he claimed would ‘confer the greatest possible benefit on the country at large’.