Calthorpe entered court under the wing of Charles, 2nd Duke of Grafton, lord chamberlain 1724-51, and under him was given employment. At the general election of 1754 he was apparently a candidate for Hindon, where his cousin, Sir Henry Calthorpe, had an interest, but withdrew on a compromise. He again came forward on a vacancy in January 1756, but was kept out by William Mabbot, Henry Fox’s candidate, endorsed by Newcastle. On the next vacancy at Hindon, in January 1758, he was returned unopposed.
Calthorpe did not stand again in 1761, but gave the nomination to Fox. ‘Mr. Blackstone’s name is given to Mr. Calthorpe with two thousand pounds’, wrote Fitzmaurice (later Shelburne) to Bute about the middle of March.
He died Mar. 1784.
