At a by-election in February 1747 Grant was returned to parliament as member for the Elgin Burghs, and on 1 April 1747 was "added to the gentlemen who are appointed to prepare and bring in a bill for taking away and abolishing the heretable jurisdictions in … Scotland". Grant took part in the debate on the second reading of the bill, and is said by Horace Walpole to have spoken "excessively well for it". This important measure of Scottish reform was subsequently carried through both houses and passed, as well as another bill, which had been introduced by the lord advocate and the English law officers, for the abolition of ward holding.