Boris Johnson defies calls to quit after he and Rishi Sunak fined

Boris Johnson has been given a fixed-penalty notice for breaking his own Covid laws by attending a party for his birthday in No 10, but he has vowed to fight on as prime minister in defiance of furious calls for him to quit.

Johnson and Sunak are thought to be the first sitting prime minister and chancellor to be criminally sanctioned. Both senior politicians were also accused of misleading parliament by previously denying they had attended parties during lockdown.

Both Labour and the Lib Dems backed calls for a recall of parliament to discuss the penalties but that is likely to be blocked by the government.

Some Conservative MPs previously suggested a line would be crossed by allowing a prime minister to remain in office if he was found to have broken the law. About 20-30 MPs were at one point thought to have submitted letters of no confidence in the prime minister, with 54 needed to trigger a leadership challenge.

If that does not materialise, the prime minister could face a further moment of danger when the Sue Gray report containing details of how the parties unfolded is published, after the police investigation ends.