Boris Johnson and Rishi Sunak are to be fined for their attendance of lockdown-breaking parties, Number 10 told reporters today.

The prime minister and chancellor are among 50 people to receive fines for illegal Downing Street parties so far, although police have yet to conclude their investigation and this number could rise.

People who breach coronavirus restrictions are given a fixed penalty notice (FPN) – a relatively low-level punishment that is handed out without the need for anyone to go to court. Instead, they can contest their innocence by refusing to pay the fine. Some 124,626 COVID-related FPNs have been issued to the public in the last two years.

The government had previously said it would not disclose the names of any ministers who were fined for attending Downing Street parties, making Sunak’s public identification by the prime minister’s spokesperson something of a surprise.

Here’s what could happen next to Johnson and Sunak.

Can they be kicked out of Parliament?

MPs are forced to immediately step down only if convicted of a serious matter – typically at least six months in jail. This fine falls way short of that.

But Parliament also has the power to trigger a ‘recall petition’ for either a criminal conviction or anything the Standards Committee deems to be misconduct. That is a lengthy process, though, and can take months or years. Even then, it ultimately depends on enough people living in their constituency signing a recall petition.

Have Johnson and Sunak now been convicted?

No. This is a fine, not a conviction. Assuming they don’t appeal, then it’s accepted that they broke the law; but their legal troubles would end with them paying the fine – there would be no court hearing, no conviction, and no further consequences.

Only if they try to appeal the fine would it go to court.

Can they be removed as ministers?

This seems much more likely.

The ministerial code sets high standards which serving government ministers must uphold. They’re much stricter rules than are required of MPs.

Ministers are expected “to behave in a way that upholds the highest standards of propriety.” This is hard to square with receiving a fine levied for breaking the law while you were a minister. Past ministers have offered to resign for much less, from “a moment of madness” in a park, to being late to Parliament.

There are also the “seven principles of public life”, which ministers must uphold. One of them is “accountability”. At least four more may apply here: integrity, openness, honesty and leadership.

What’s more, the Ministerial Code states that it “should be read against the background of the overarching duty on ministers to comply with the law and to protect the integrity of public life”.

Incidentally, the foreword to the code was written by Johnson himself. It says that to “win back the trust of the British people, we must uphold the very highest standards of propriety”. It adds: “The precious principles of public life enshrined in this document – integrity, objectivity, accountability, transparency, honesty and leadership in the public interest – must be honoured at all times.”

Could Parliament make them resign?

Theoretically, yes.

Under the ministerial code, “ministers have a duty to Parliament to account, and be held to account” for their “actions”. In particular, “it is of paramount importance that ministers give accurate and truthful information to Parliament, correcting any inadvertent error at the earliest opportunity”.

“Ministers who knowingly mislead Parliament will be expected to offer their resignation,” which could make life very difficult for Johnson, given his earlier categorical denials in Parliament.

The main complication is that Johnson still – theoretically – controls the House of Commons through the large majority of Conservative MPs. A large number of Tory MPs would need to rebel or abstain from a vote for the prime minister to be unseated. This has not happened since 1940; and it has never happened in the context of a prime minister being removed for lying to Parliament.

But the rules do say that Johnson should resign if he lied to MPs?

This is where it gets complicated. The way the rules are phrased, “ministers who knowingly mislead Parliament will be expected to offer their resignation to the prime minister”.

It could be argued that this rule does not apply to the PM – although many would disagree with that.

Like all the standards rules drawn up after the “Tory sleaze” scandals in the 1990s, the assumption was that however many “bad apples” in the government, the prime minister would be someone of unimpeachable integrity.

The rulebook was never designed for a PM who lies.

Would one of them resigning affect the other?

Informally, yes.

If Sunak were to resign, saying that (for instance) ministers need to take responsibility for the consequences of their actions, it would make things much harder for Johnson.

This could be a Geoffrey Howe moment – Margaret Thatcher’s long-serving deputy resigned in 1990 with a blistering attack speech that described the “conflict of loyalties” he faced. Thatcher was gone barely two weeks later.

Could Johnson and Sunak ignore all the rules, and just carry on?

Why not? It’s what this government has done many times before – most notably after Johnson was accused of misleading the Queen over proroguing Parliament in 2019, he just carried on.