The Anti-Canadian opinions he expressed in his newspaper gave him the nickname of "Dr. Slop" in the Vindicator and Canadian Advertiser edited by patriot Edmund Bailey O'Callaghan.
In February 1836, he published the Anti-Gallic Letters, a collection of texts addressed to Gosford, which he originally signed under the pseudonym of Camillus in the Montreal Herald between September 1835 and January 1836.
On 25 August 1838, Lord Durham who replaced Gosford, appointed him assistant commissioner in the commission on municipal administration presided by Charles Buller.
He became the spokesman of Durham and the paper he wrote with fellow assistant commissioner William Kennedy was included in the Report on the Affairs of British North America.
He left England for Red River Colony to fill the position of recorder offered to him by George Simpson, governor of the Hudson's Bay Company.
He entered in conflict with the Métis, which were mainly French-speaking and Catholic, when he recommended the governor Assiniboia, Alexander Christie, to repress the business of small independent fur traders on the company's territory.
He was however unconditionally released and permitted to keep the furs in spite of the verdict, because the Métis who attended the trial, Louis Riel Sr. at their head, made it clear they were not going to let it happen.
During a special meeting on 31 May 1849, the Council of Assiniboia arrived to a compromise with Thom, who agreed to make use of the French language in the performance of his duties.