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Boris Johnson held firm on his “do-or-die” promise to take the UK out of the EU on 31 October, clashing with the Irish taoiseach, Leo Varadkar, and sending his special EU envoy to Brussels to deliver the message that the UK will leave without a deal unless the bloc abolishes the Irish backstop.

In comments that suggest he is preparing to blame the EU if the UK crashes out, Johnson said he was not aiming for a no-deal Brexit but there could be no further meaningful talks without a radical EU rethink on the backstop and the situation was “very much up to our friends and partners across the Channel”.

However, the weakness of the prime minister’s position was underlined when the Liberal Democrats won the Brecon and Radnorshire byelection, cutting his majority to one, and hardline Tory eurosceptic rebels said they would block any attempt to pass Theresa May’s withdrawal agreement again even if the backstop is removed.

Johnson faces equally strong opposition from the left of his party, with moderate Tory supporters of a second referendum threatening to cross the House of Commons in order to foil Brexit – prompting urgent warnings that the new prime minister could rapidly lose control of parliament.

The health secretary, Matt Hancock, did nothing to quell speculation about an autumn general election by announcing – in one of the most pro-Brexit areas of the country – that an “extra” £1.8bn would still be spent on NHS infrastructure and equipment even in the event of a no-deal Brexit.

Meanwhile, warnings of the consequences of leaving without a deal continued to come thick and fast: from Varadkar, who said we “should all be afraid” of it; the Bank of England, which said there was a one in three chance of a Brexit recession; and currency traders, who sent sterling to a new low.

As evidence was published by the Lib Dems that companies that export only to the EU are largely unprepared for a no-deal Brexit, all English councils were instructed to appoint a “Brexit lead” to work with the government in preparing for the possibility that the UK will leave without an agreement.

Brexit will take place on 31 October “whatever the circumstances”, No 10 insisted, refusing to say whether a parliamentary vote against no deal, a no-confidence vote in the prime minister or even a general election campaign would be considered sufficient reasons for it to change course.

Brussels has certainly got the message: after the meeting between the prime minister’s chief envoy and senior EU figures, European diplomats were told Johnson has no intention whatsoever of renegotiating the withdrawal agreement and a no-deal Brexit is now his “central scenario”.

What next?

It appears more and more likely that Johnson and his key adviser, Vote Leave mastermind Dominic Cummings, are indeed planning to take Britain out on 31 October regardless of what may happen in parliament – and perhaps in the middle of an election campaign.

Many observers are now assuming No 10 is calculating that with Brexit delivered, the Tory party could unite the leave vote, obliterate Nigel Farage’s Brexit party altogether, and trounce the disheartened forces campaigning for a second referendum.

Is that really the plan? Who knows. In the meantime, Jessica Elgot explains how the prime minister’s parliamentary majority could vanish, while Peter Walker and Seán Clarke examine the likely impact of a no-deal Brexit (spoiler: it’s not good).

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In the Guardian, Matthew d’Ancona works through how the next few months might pan out … It’s not pretty:

When parliament returns on 3 September, the government will certainly face a vote of no confidence if it is still on course for a no-deal Brexit. Under the Fixed-term Parliaments Act 2011, a vote of no confidence in the government would trigger a two-week scramble to form a new administration. If that quest failed – as it would – an election would be triggered. The Electoral Registration and Administration Act 2013 requires 25 working days between the dissolution of parliament and polling day. To squeeze in an election before Brexit day would require a vote of no confidence as soon as the Commons returned; the pre-emptive cancellation of the party conferences; a fortnight of pointless attempts to form an alternative government ending on, say, 17 September; and a snap election held after the minimum five-week campaign on Thursday, 24 October. Johnson wins, and Britain leaves a week later. How likely is it that this precise sequence will fall into place? How often does politics observe such neat patterns? It is more likely, indeed, that 31 October could fall in the middle of an election campaign – or even (since it is a Thursday) on polling day itself. Geoffrey Cox, the attorney general, believes there is no legal impediment to the UK leaving Europe even as rosette-bearing politicians crisscross the nation in battle buses. Already, the pro-remain campaigner Gina Miller is investigating the potential for a judicial review of this grotesque possibility. For how odd would it be for an election about Brexit, triggered by a confidence vote caused by Brexit, and framed by the prime minister’s readiness to embrace a no-deal Brexit, to be made both redundant and ridiculous in real time by Brexit happening anyway, in the thick of electoral battle? One might ask, more pithily: how the hell did we get here? Yet such are the times in which we live, and such are the worse ones towards which we are heading.

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Plunging pound - the Financial Times’ forex expert tells all: