On an election petition, Fitzroy Kelly and Robert Adam Dundas, the members, were unseated and Morrison, with Rigby Wason, headed the poll in June 1835.
At the succeeding dissolution, in July 1837, Morrison remained out of parliament and, in the following December, on the occasion of a by-election for a vacancy at Ipswich, he was defeated in a contest with Joseph Bailey.
In March 1840, he re-entered the House of Commons as member for the Inverness Burghs and was again returned unopposed in the general election of 1841 but, on the dissolution of 1847, in poor health, he finally retired.
In 1845, he moved similar resolutions and, again in March 1846, when he finally succeeded in obtaining a select committee for the better promoting and securing of the interests of the public in railway acts.
It included works by Constable, Da Vinci, Hogarth, Holbein, Poussin, Rembrandt, Reynolds, Rubens, Titian, Turner, Cuyp, Jan Steen, Murillo and Van Dyck.