In setting the scene for Boris Johnson's first and potentially historic speech as prime minister to Tory Party Conference, Downing Street made two statements that sounded a lot like threats, both to EU leaders and to opposition MPs.

In tearing up the 2017 Joint Report that underlies the so-called backstop to keep open the border on the island of Ireland - that foundation of the Brexit deal agreed by Theresa May and ditched by Johnson - Downing Street said "officials have made it clear that if Brussels does not engage with the offer...then this government will not negotiate further until we have left the EU".

In other words, Johnson wants to know pronto whether the EU is prepared to ditch two of its reddest lines:

Both that it would allow infrastructure for customs checks somewhere on the island of Ireland, though away from the border (contrary to the Joint Report) and that any bridging arrangements (or backstop) to keep open the border between Northern Ireland and the Republic pending long-term solutions do not include the risk of permanent membership of the customs union.

A member of Johnson's team told me yesterday, it should be clear by the end of next week whether an entente is reachable - after negotiators enter a "dark tunnel".

In fact I think we will know much earlier, possibly even tonight whether the gulf between Johnson and the EU is remotely bridgeable - and whether his government then concentrates exclusively on mitigating the impact of a no-deal Brexit (though the PM will spend coming days on a whistlestop tour of European capitals trying to woo EU leaders).

The other inflammatory statement from Downing Street, attributed to a "senior Number 10 official" (I think we all know who that is), said that if the talks flop, "this government will not negotiate [Brexit] delay" and "the EU is obliged by EU law only to negotiate with member state governments".

Dominic Cummings is the prime minister's most senior aide. Credit: PA

Which was of course Johnson and Dominic Cummings goading MPs, "if you don't like what we're doing, throw us out, because if we're here you're not getting your Brexit delay".

So this is it. No more can kicking. By next week we'll know if it is deal or no-deal, while Johnson is in charge.

And MPs will therefore have to decide whether now is the moment for that vote of no confidence, whether with no-deal looming, it's Johnson or no-Johnson.

MPs have the option of amending the Benn Act to empower the Speaker John Bercow to ask EU leaders for a Brexit delay if Johnson refuses. But they know that if Johnson remains in 10 Downing Street, he will do all he can to obstruct that postponement - and they can't be certain he won't succeed.

We've waited long enough, and in this Brexit-induced constitutional and political crisis we've reached apotheosis. We are at peak mayhem.