Why did Boris Johnson have to apologize?

The Prime Minister was fined by the Metropolitan Police in London for violating lockdown rules. He and his wife Carrie, along with the finance minister Rishi Sunak and other government staff, were sent fixed penalty notices. They broke the law at the time and were caught.

The Prime Minister also previously denied having attended any parties and said on more than one occasion that all guidelines at Downing Street had been followed.

Before he had the chance to speak in parliament it was already ruled that MPs could debate the Prime Minister's actions later in the week with a vote on whether to refer him to the common's privileges committee: a committee of seven MPs presiding over conduct such as misleading parliament.

What did he have to say?

Johnson offered the same apology he had made a few days before to the British public. He said he acknowledged the hurt and anger caused, and said people had the right to expect better from their prime minister.

He said that "not by way of mitigation or excuse" but to clarify matters to the House, it did not occur to him the gathering in the Cabinet Room on his birthday could amount to a breach of the rules.

He said that was his mistake, "and I apologise for it unreservedly."

What was the reaction from MPs?

In one of the most vitriolic attacks ever launched from Kier Starmer, the opposition leader called his apology "mealy-mouthed" and said it was "a joke".

This isn't a "fixable glitch," he said, but "what he does and who he is." 

"He is dishonest," Starmer said, "incapable of changing and drags everyone else down with him."

The Scottish National Party leader Ian Blackford urged Conservative MPs to "grow a spine" and remove Johnson as their leader.

Will he survive as PM?

This is a more complicated question. The Prime Minister and indeed the finance minister can resign at any time. There was speculation that Sunak might resign, but he didn't. There has never really been any question that Johnson would resign, simply because of his character.

There are only two ways a prime minister can be removed from office. Most obviously, he or she can lose a general election, but in this case the next one is scheduled for no later than January 2025.

Or the prime minister can be removed by losing an internal leadership competition organised by his own party. In this case, this would need 54 Conservative MPs (15 percent of the membership) to write letters expressing a lack of confidence in the prime minister. But it would also need a potential challenger for rebel MPs to support.

However, Thursday's vote in Parliament does technically offer a third route. 

If MPs vote on Thursday to refer the prime minister to the Privileges Committee, its recommendations could be damning. If the committee concludes that Johnson misled parliament then he has breached an established code which should lead to resignation.

However, MPs will have to vote again on any committee conclusion and Johnson still has a large majority.