Dawnay stood for Cirencester on a joint interest with Benjamin Bathurst and was returned unopposed. His brother, Lord Downe, wrote to Newcastle on 3 Dec. 1753: ‘Your Grace has gained a zealous friend in my brother and the Whigs a very steady man.’
But by spring 1767 he had become a follower of Rockingham. He voted against the court on the land tax, 27 Feb. 1767, and wrote to Rockingham on 9 Mar. 1767, on receiving his whip for the East India inquiry:
Your Lordship may depend on my attendance this day; and I wish my abilities were greater, that I might be more useful to your Lordship, that is, to my country, for no person living is more thoroughly persuaded than myself that all your Lordship’s views ... are directed to the benefit of that single object.
He voted for the nullum tempus bill, 17 Feb. 1768.
In 1765 he sold his Ampney Crucis estate, and with it his interest at Cirencester. In December 1767 Rockingham offered to bring him into Parliament at the general election,
He died 21 Dec. 1780.
