The Supreme Court ruling dominates the front pages.
"He misled the Queen, the people and parliament", is the Guardian's headline. It describes the judgement as a crushing unanimous verdict against the prime minister.
The Daily Telegraph says the justices chose the most extreme possible course of action.
For the Financial Times, the court has dealt a severe blow to Boris Johnson's authority, and MPs are returning to Westminster seeking retribution.
The Mirror's front page has pictures of Britain's shortest serving prime ministers - and suggests that, after just 63 days in the job, Mr Johnson could break the record. "There's a special place in history waiting for you, prime minister", is the headline.
Other front pages draw attention to the battle for supremacy between the executive and the judiciary. The Daily Mail's headline quotes what it calls a senior ally of the prime minister as asking: "Who runs Britain?"
The Daily Express headline also questions the court ruling: "Unlawful? What's lawful about denying 17.4 million people Brexit?"
The Sun's main story focuses on the reaction of its readers - saying they expressed fury, and bombarded the paper with messages of support for the prime minister.
The Financial Times, the Guardian and the Mirror all call on Mr Johnson to quit.
In the view of the FT, faced with such a damning judgement, any premier with a shred of respect for British democracy and the responsibilities of his office would resign.
But the Guardian says he won't go because he has no honour and no shame. The precedent such an act of defiance sets ought to be unthinkable, it adds.
Other leader writers turn their fire on MPs and judges.
The Sun accuses the Supreme Court of doing the bidding of Remainer MPs. In one act of constitutional vandalism, it says, 11 judges have become an unelected political entity, granting themselves immense power to overrule the government.
The Mail says the only way to resolve Brexit now is for the opposition parties to agree to a general election - but, it adds, they are terrified of the prime minister's popularity with voters and his determination to leave the EU.
There's plenty of interest in the president of the Supreme Court, Lady Hale, who delivered the judgement.
The i says many watching the televised hearing were captivated by her large spider brooch. For the Guardian, it had the optics that made it a story of its own.
By the end of the afternoon, the Times says, she had become an internet star. Inspired by the brooch, Macer Hall in the Express writes that she "ensnared" Boris Johnson in a tangled legal and political web.
The Mail's Andrew Pierce says Lady Hale is famed on the court circuit for her oversized insect and animal brooches - including a frog and a butterfly.