He was head of the Ministry of Defence and sent one of his secondary ministers, Horatio Chinn, to investigate UNIT. The Minister disliked Chinn and when they talked, the Minister made frequent references to the man about his incompetence and chances of being fired. When the Axos affair started, he granted Chinn special powers to secure Axonite for the UK and not the UN (including arresting UNIT). When this leaked out, the government was embarrassed and he threatened to sack Chinn unless he successfully distributed Axonite worldwide. (TV: The Claws of Axos)
During the escalation of World War III, the Minister spoke over the phone to Brigadier Lethbridge-Stewart about Sir Reginald Styles and the "ghost" he had apparently encountered in Auderly House. (TV: Day of the Daleks)
Behind the scenes
In the novelisation of The Claws of Axos, the Defence Minister was replaced with the Minister of Security. Here, the Minister is deliberately trying to undermine UNIT - and hopefully get rid of Chinn - by sending Chinn to investigate them, as their UN status interferes with the new Ministry of Security's attempt to bring all the intelligence agencies under one roof.