By 1764 he was making £2,000 a year, helped by his pamphlet,[4] drawn up by Dunning on behalf of the directors of the English East India Company.

[3] In 1766 Dunning was appointed recorder of Bristol, and on 28 January 1768 he became Solicitor-General in the Duke of Grafton's administration, in the place of Edward Willes, who was raised to the bench.

On 9 January 1770 Dunning both spoke in favour of the amendment to the address urging an inquiry into the causes of "the unhappy discontents which at present prevail in every part of his majesty's dominions"; and a few days later tendered his resignation.

On 6 November 1776 he supported Lord John Cavendish's defeated motion for the "revisal of all acts of parliament by which his majesty's subjects in America think themselves aggrieved".

In the next session Dunning, continued to oppose the ministry, and was instrumental in obtaining the insertion of a clause in the bill for the suspension of habeas corpus, which lessened its scope.

[3] On 14 May 1778 Dunning seconded Sir George Savile's motion for leave to bring in a bill for the relief of Roman Catholics; and it was on his amendment that the house unanimously voted that a monument should be erected in Westminster Abbey to the memory of the Earl of Chatham.

On 21 February 1780 he supported Savile's motion for an account of crown pensions; and on 6 April moved his famous resolutions that "the influence of the crown has increased, is increasing, and ought to be diminished", and that "it is competent to this house to examine into and correct abuses in the expenditure of the civil list revenues, as well as in every other branch of the public revenue, whenever it shall appear expedient to the wisdom of the house so to do".

In February 1782 he supported Conway's motion against the further prosecution of the American war, and a month later announced that arrangements were being made for the formation of a new ministry.

In 1805, Elizabeth built to the designs of John Nash a villa rustica country house at Sandridge Park in the parish of Stoke Gabriel.