This is by Reginald Bretnor writing under the name of Grendel Briarton.

Soon after A Budget of Musings Afloat and Ashore, by ‘An Old Salt,’ appeared in 3412, Vice-Admiral Sir Trumpery Buckett invited Ferdinand Feghoot to visit the 18th Century and meet Madame Pompadour. Though his manner seemed odd, Feghoot accepted; and they left via the )( at the Time Travellers Club.

To Feghoot’s surprise, they emerged not in France, but on a dark London street where a mob was storming and roaring.

“Feghoot,” Sir Trumpery gloated, “I have trapped you. That was my book you reviewed. You called it ‘a slop- chest of moth-eaten jottings, a dull, ill-assorted olla podrida.’ Well-” He pointed at the oncoming mob. “-here’s my revenge! These are the Gordon Riots, my boy-the zenith of British anti-Catholicism. You have boasted that nothing can force you to utter a bigoted word against any religion. Ha! You will now if you want to survive!” And he roared with laughter.

“DOWN WITH PRIESTS! PAPISTS GO HOME!” the mob bellowed.

A huge Scotsman came up, brandishing billhook and torch — and Feghoot at once began yelling as loudly as anyone else.

“I thought so,” Sir Trumpery sneered. “This will make a fine story. ”

“But I’m not against any religion — I’m denouncing your miserable book! NO POTPOURRI” shouted Ferdinand Feghoot.

(Copyright © 1957 by Mercury Press. First published in THE MAGAZINE OF FANTASY & SCIENCE FICTION, February 1957.).