“If it’s OK for the prime minister to say whatever they want when questioned by the House of Commons and then just say ‘Oh well, I genuinely thought that was true and now I realize that it’s not,’ then there is no actual mechanism for the House of Commons to hold the government to account,” she said.
Mr. Johnson will face a vote on Thursday on whether his conduct should be referred to a formal parliamentary investigation. With a roughly 80-seat Conservative majority, that is highly unlikely to happen. But it will have the effect of putting Conservative lawmakers on the record in their support of Mr. Johnson — something that opponents could use against them in future elections.
On Tuesday, opposition leaders offered a tangy foretaste of those attacks.
“A lawbreaking prime minister — just dwell on this,” said Ian Blackford, the leader of the Scottish National Party in the British Parliament. “A prime minister who has broken the law and remains under investigation over additional lawbreaking. Not just a lawbreaker, a serial offender. If he has any decency, any dignity, he would not just apologize; he would resign.”
Nor are critics impressed with the way that Mr. Johnson’s allies have compared the fine he was given for breaking lockdown laws with a speeding ticket. The prime minister steered clear of that comparison on Tuesday.
For the critics, the biggest cost of the scandal may be diminished public trust in government. Covid restrictions were particularly hard on families with relatives who ended up in the hospital, where they sometimes died alone, barred from seeing their loved ones. Many of those people have expressed outrage that Mr. Johnson and his colleagues, who imposed those rules, did not abide by them.
“In our strange Constitution, all depends on public feeling,” Professor Bogdanor said. “If the public feels strongly enough, they could compel a prime ministerial resignation by writing to their M.P.s, by Conservative voluntary workers refusing to do voluntary work, and by votes in the local elections.”
As it happens, Britain will hold local elections on May 5. They loom as perhaps the ultimate test of whether Mr. Johnson will survive this scandal.