Montagu is best known for his highly publicised dispute with Sir John Franklin, the famed polar explorer who held the office of Lieutenant-Governor of Van Diemen's Land at the time.

Franklin's subsequent removal from office meant he would be available for command of the Royal Navy's renewed attempt to complete the charting of the Northwest Passage, through the Arctic archipelago.

Montagu, however, went to England and so successfully brought his case before Lord Stanley, the Secretary of State for War and the Colonies, that Governor Franklin was recalled.

Soon after his arrival he "ascertained that there was a large amount of revenue many years overdue, and set about collecting it with an intensity of purpose from which even pity for the distressed was absent".

[3] Montagu introduced a system of constructing roads by convict labour, and worked with great energy for the good of the colonies in many other directions.

Montagu, who had suffered losses in connection with his transfer from Van Diemen's Land, died poor, and a civil list pension of £300 a year was granted to his widow.