1st Baronet. The Calvert, later Verney Baronetcy, of Claydon House in the County of Buckingham, was created in the Baronetage of the United Kingdom on 3 December 1818.

At the age of fifteen, was commissioned into the 23rd Foot (Royal Welsh Fusiliers). The following year he served with his regiment in America during the American Revolutionary War.[1] He was at the siege of Charleston, and served through the campaign of Lord Cornwallis which ended with the surrender of Yorktown.[1] From 1781 to 1783 he was a prisoner of war.

Returning to England in 1784, he next saw active service in 1793 in the Low Countries, where he was aide-de-camp to the Duke of York, and in 1795 was engaged on a confidential mission to Brunswick and Berlin. In 1799, having already served as deputy Adjutant-General, he was made Adjutant-General to the Forces. In this capacity he effected many improvements in the organization and discipline of the service. He greatly improved the administration of the army medical and hospital department, introduced regimental schools, developed the two existing military colleges (since united at Sandhurst), and was largely responsible for the founding of the Duke of York's School, Chelsea.

In recognition of his work as adjutant general he was made a GCB in 1815, and, on retiring from office, received a baronetcy in 1818. In 1820 he was made Lieutenant-Governor of the Royal Hospital Chelsea.