LONDON — Britain’s beleaguered Prime Minister Boris Johnson is fighting for his political future Wednesday, after two of his top Cabinet ministers walked out of their jobs and a string of more junior ministers resigned following months of political chaos.

Many opponents, including those within his own Conservative Party, have openly called for Johnson to go. But he has shown no sign of quitting, and it may be up to a small but powerful Conservative group known as the 1922 Committee to oust him before the next general election.

Here’s a look at how that could happen:

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CAN A NO-CONFIDENCE VOTE TAKE PLACE?

Technically, not for another 11 months.

A no-confidence vote is triggered if 15% of Conservative lawmakers — currently 54 — write to Graham Brady, head of the 1922 Committee, to request it.

Johnson survived a confidence vote on Jun. 6, though the scale of the revolt — 41% of his own lawmakers voted against him — left his future in doubt.

Under current party rules, a year must pass before another formal leadership challenge can take place.

But the 1922 Committee has the power to change the rules to allow a fresh confidence vote sooner.

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WHAT IS THE 1922 COMMITTEE?

The 1922 Committee is a group of about a dozen Conservative backbenchers — legislators who hold no government office — who meet regularly to discuss party matters. It meets with the party leader monthly to represent the views of the rank and file within the party.

Crucially, the group determines the rules under which a sitting leader can be challenged.

The committee was named because a group of lawmakers elected in 1922 formed it — albeit in 1923.

Its members are elected by all Conservative backbenchers, and the committee is due to elect a new executive committee within coming weeks.

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HOW LIKELY WILL THE RULES CHANGE?

That’s up to the 1922 Committee executive. Some news reports suggest a decision could even come later Wednesday, when the executive meets.

Or the committee may wait a few weeks until after its new executive is elected. Several Conservative lawmakers have said they will stand for the committee and vote for a rule change if elected.

Bob Blackman, the committee’s joint executive secretary, said Wednesday he believed a “very high threshold” needs to be reached to warrant a confidence vote so soon after last month’s ballot.

“What we have to do is certainly have calm heads here, because one of the other suggestions being made … is that you’d reduce the timeframe to six months. Six months takes you to the beginning of December,” he told TalkTV.

“In my view, you’d have to have a very high threshold indeed to warrant confidence votes very soon after a previous confidence vote,” he said.