A few Conservative MPs have (anonymously) been giving us their reaction to this afternoon's news.
One Welsh MP tells the BBC: "Support for Ukraine has been outstanding - to defenestrate the PM at this moment would be unbelievable folly."
Asked if the PM could survive being fined by the police, a senior backbencher says: “For any other politician, this would not be survivable.
"Rishi may be done for, he [the PM] will try to brazen it out, but this is a big thing, people knew others would be fined, but him being fined himself, well looking at the WhatsApp groups I think people are still trying to process this.”
An MP from the 2019 intake said they were going to have "a long think" about whether Johnson should step down.
"There is now another cabinet minister [Sunak] involved, which leaves Liz Truss [the foreign secretary] as the alternative. We have got to have the best person running the country, and if he does go what does that mean?"