British Prime Minister Boris Johnson is on the brink of facing a leadership challenge, according to reports, after an angry backlash over claims parties were held at his residence during coronavirus lockdowns.

After Johnson denied an accusation by his former adviser that he had lied to parliament about one party, the Daily Telegraph and ITV News, citing sources, said the required number of letters from his own lawmakers calling for a no-confidence vote in his leadership could be reached on Wednesday.

As many as 20 Conservative lawmakers who won their seats at the last general election in 2019 plan to submit letters of no confidence in Johnson, the Telegraph reported.