In May 1782 Adamson announced his candidature for the reformed constituency of Cricklade, in opposition to G. R. St. John, Robert Nicholas, and Samuel Petrie. He was considered a supporter of Lord North. Finding himself the weakest of the contestants, he negotiated a compromise with St. John, and stood down in his favour.
At the general election in 1784 he came forward again, in partnership with his cousin C. W. Coxe, and stood against Nicholas and J. W. Heneage, supporters of Pitt.
Adamson does not appear to have sought to reenter Parliament. He died 17 Sept. 1817.
