No one is remotely indispensable. UK PM Boris Johnson declared his resignation on July 7, 2022 amid controversies about him. He remains in office in a caretaker capacity pending the Conservatives' leadership election.
In 2019, Johnson was elected Conservative leader and appointed prime minister. He re-opened Brexit negotiations and in early September controversially prorogued Parliament; the Supreme Court ruled the action unlawful later that month.
After agreeing to a revised Brexit withdrawal agreement with the EU, which replaced the Irish backstop with a new Northern Ireland Protocol, but failing to win parliamentary support for the agreement, Johnson called a snap election for December 2019 in which he led the Conservative Party to victory with 43.6 per cent of the vote, and the party's largest seat share since 1987.
On 31 January 2020, the United Kingdom withdrew from the EU, entering into a transition period and trade negotiations leading to the EU–UK Trade and Cooperation Agreement. The COVID-19 pandemic became a major issue of his premiership; the government responded with various emergency powers, introduced measures across society to mitigate its impact, and approved the rollout of a nationwide vaccination programme.
However, he faced a controversy known as "Partygate" over his breaching of COVID-19 regulations and receipt of a fixed penalty notice, when he became the first British prime minister to be sanctioned for breaking the law while in office. The publishing of the Sue Gray report and a widespread sense of dissatisfaction led to a confidence vote in his leadership among Conservative MPs in June 2022, which he survived.
Revelations in July 2022 over his hiring of Chris Pincher as Government Deputy Chief Whip, however, led to a mass resignation of members of the government and to Johnson resigning as party leader.
Thank You Mr. Prime Minister for getting Brexit done, trying to lead UK during the pandemic, and helping Ukraine in its fight against Russia but I guess it's for the greater good that you leave now. I'm not judging him and hopefully he will clear his name.
But Public Office is a Public Trust. In leadership position integrity is paramount. If he clears his name maybe he could try to apply for the No. 10 Downing Street position.