Clerk’s youth and inexperience made him a surprising and controversial choice to step into the 2nd Earl Melville’s shoes as Member for Edinburghshire in 1811, despite the undoubted respectability of his family; indeed he was regarded in opposition circles as a mere creature of Melville’s family, holding the seat until Lord Chief Baron Dundas’s son came of age. He survived contests in 1811, 1812 and 1818 thanks to the strength of the interest that sponsored him, and though reported in 1816 to be a source of dissatisfaction to his sponsors, retained the seat, for which they did not provide a family candidate, until his defeat in 1832.
In Parliament he could be counted on to support government. In his maiden speech he unsuccessfully proposed a clause in the distillery bill to prevent English distillers defrauding the revenue to the disadvantage of Scotch distillers, 22 Jan. He voted with ministers against the abolition of the sinecure paymastership, 21, 24 Feb. 1812, and against the motion for a stronger administration, 21 May. At his re-election in October 1812 he promised to continue in the same line, espousing the principles of Pitt, though opposing parliamentary reform and Catholic relief, against which he voted on 2 Mar., 11 and 24 May 1813, also on 9 May 1817.
On being re-elected in 1818 he praised the record of the government in war and peace.
