He served on committees to examine the public debt (1798), the Irish exchange (1804), public expenditure (1807) and the bullion committee (1810), which scrutinized the high price of gold, foreign exchange, and the state of the British currency. The report of the committee, written by Thornton, argued for the resumption of gold payments in exchange for notes and deposits, which the Bank of England (of which his elder brother, Samuel Thornton, was a director) had suspended in 1797, but the recommendation was not well received at the time, and gold redemption on demand was not restored until 1821. In the next few years he continued to press for these measures to be implemented, publishing two reports in 1811.