It is quite clear now by its actions that this government is heading towards the disaster that would be a no deal leaving of the European Union. It is the British government that intends to leave and thus its duty to come up with proposals. It hasn't even bothered to make the effort. It holds a gun to its and our head and thinks that its threat to commit suicide will bring the other party to heel.
Even the Irish, who will lose the most after the UK, will not be pushed by something the British are doing. And if we crash out, then the demand for a trade deal will first have to be met by a withdrawal deal, including how to secure a free-flowing Irish border.
We need here to argue first principles, as laid out by Jonathan Sumption in the second Reith Lecture in 2019. We are a representative democracy, and this comes first and foremost, and what we this does - by giving selected people time and pay to consider - is absorb the concerns of minorities and allow for change. We do not do direct democracy, even though we could, which is a snapshot in time when each person considers no more than themselves.
Parliament, therefore, has every right and constitutional duty to consider and act differently, and in law that snapshot in time referendum was advisory. It doesn't matter that the government then said it would abide by the result. That government has since passed, and no House of Commons decision ever binds the House of Commons from changing its mind.
There is about a week for a vote of no confidence to happen that gets to a full new government before the exit date, so more or less the House has to move straight to such a vote. However, the second option is looking more and more likely, which is where the Fixed-term Parliaments Act provides for a fortnight to try a different Prime Minister to command the House. If Boris Johnson, on losing a vote, refused to resign, then indeed he would be sacked by the monarch in favour of someone who could. Labour says it would go to a General Election directly, but it would be foolish if a resultant government was only active after the leave date. It would be necessary to have a temporary executive to pass ask for a delay and pass delay legislation (removing a leave date in the future - a 'default position' prior to a General Election). Is Labour really going to sabotage this country because it wants power? Would it get such power, ever, the electorate having known that it deliberately allowed a no deal by lack of time to stop it?
And a note for the Liberal Democrats. They should make it clear that a vote for them into government is the equivalent of a second referendum. If they were (high odds, unlikely - but stranger things have happened) to form the government, that is a mandate in itself to revoke Article 50 altogether.
We have a government now chucking money about like it is confetti, so long as it is money that makes the headlines. It's a fake government, and it is time to bring this nonsense to an end. No one is fooled by Boris Johnson: he is a campaigner but he isn't believed by those who matter, and by an increasing proportion of the electorate. So we know where we are and it is soon time to unseat him.