The UK’s former Prime Minister, Boris Johnson, has announced his resignation as a member of Parliament, accusing a parliamentary probe into the “party gate” scandal of driving him out.

Johnson, 58, said he was stepping down on Friday with immediate effect, “triggering an immediate by-election” in his marginal seat, which heaped political pressure on his successor, Rishi Sunak.

Johnson had been fighting for his political future with a parliamentary inquiry investigating whether he misled the House of Commons when he said all COVID-19 rules were followed.