LONDON — In one of his first acts as the leader of Britain’s House of Commons, Jacob Rees-Mogg this past week laid down a few rules for written communication by civil servants who work in his office.

“Non-titled males” must be addressed as “Esq.” All measurements should be imperial, not metric. Two spaces should follow a period. And 18 words or phrases, including “very,” “got,” “ongoing,” “equal,” “unacceptable” and “I am pleased to learn” were now banned.

His memo made its way to the broadcaster ITV, which published excerpts on Friday, prompting a wave of grammatical discussion and political mockery that had yet to subside a day later.

Leader of the House is Mr. Rees-Mogg’s first cabinet-level position, as part of the team of hard-line Brexit enthusiasts appointed this past week by Britain’s new prime minister, Boris Johnson. But this latest controversy is far from Mr. Rees-Mogg’s first time as a social-media sensation.