In his first European trip as prime minister, Mr Johnson attended a meeting with the German chancellor, where he was expected to spell out his commitment to taking the UK out of the EU on 31 October, with or without a deal.
It comes as Irish foreign minister Simon Coveney warned no deal was more likely than ever, a view echoed by the French government, according to diplomatic sources.
Here's how we covered developments as they happened:
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Boris Johnson flies to the continent today and is set on a collision course with EU leaders after they rejected his demand to scrap the Irish backstop.
Brussels issued a damning dismissal of Mr Johnson’s call to scrap the policy, while Angela Merkel said a “practical solution” would have to be found without reopening the withdrawal agreement negotiated by Theresa May.
Mr Johnson had sent a letter to EU officials calling for the Irish border backstop to be removed from the Brexit withdrawal agreement but presented no alternative to the policy.
The holidays are nearly over - and it's shaping up to be a busy few days for Boris Johnson.
The PM will be in Berlin later where he will discuss Brexit-related issues with the German premier Angela Merkel over dinner, before heading to Paris on Thursday to meet French president Emmanuel Macron.
On Saturday, Mr Johnson will be at the G7 summit where he will meet other world leaders including US president Donald Trump.
The meetings come as Mr Johnson has reiterated his opposition to the Northern Irish backstop, saying he will not support any withdrawal agreement that includes it.
Robert Jenrick, the housing secretary, has insisted it is "entirely possible" for Mr Johnson to secure a Brexit deal, but removing the backstop offered the "only prospect of securing a deal".
He told BBC Radio 4's Today programme: "He's (Mr Johnson) saying... he will negotiate energetically in the pursuit of a deal, he's very happy to sit down and to talk to EU leaders, but he's making clear that the backstop needs to be removed, that is the only prospect of securing a deal."
He added: "If we have a very credible option to leave on October 31... if we do that and we make clear to the EU that we want to secure a deal, we want to leave in an orderly way that works both for us and for our friends in the EU, but that the only way to do that is to reopen the Withdrawal Agreement, remove the backstop."
Boris Johnson will pull British officials and ministers out of most EU decision-making meetings from September as the government gears up for the Brexit deadline.
Civil servants and ministers will now only attend EU meetings where the UK has a significant national interest in the outcome, such as on security.
The move comes after the prime minister vowed to "unshackle" diplomats in Brussels to employ their talents elsewhere, as Whitehall braces for a looming no-deal departure from the EU.
Ex-culture minister Ed Vaizey has said Boris Johnson was "just going through the motions" with his visits to European capitals and was "hell-bent on getting no deal".
He said the "real onus now" was on parliament to show that it was willing to pass a Withdrawal Agreement, adding that talk of a government of national unity was "completely for the birds".
The Tory MP told BBC Radio 4's Today programme: "Well I'm not going to vote no confidence in the government. I will look at any measures that could prevent no-deal happening, but my challenge to my anti no-deal colleagues, and I totally respect their position and my position is where does that get us?
"Where does an extension get us? It delays it by six months to a year, it doesn't solve the problem."
Former German ambassador to the UK, Thomas Matussek warned there were "certain issues on which the EU cannot budge" and those who thought the EU might make eleventh hour concessions "might be in for a nasty surprise".
He told Today: "We cannot throw Ireland under the bus, what message would that send to other members of the EU family if we gave up that sort of loyalty and solidarity?"
Asked if the EU could make last-minute concessions to the UK over Brexit, he said: "Well I think this time it might be wrong because I think it's important if you try to put yourself into the shoes of your partner and the clear assessment of the interests of both sides indicate that there are certain issues on which the EU cannot budge and these are the four freedoms. So I think they might be in for a nasty surprise."
He added: "Of course if we see and listen to parliamentarians and to people who show more understanding of what Europe is, we think there might be a glimmer of hope, but I think they will continue keeping out of the internal British debate."
NEW: Transport secretary Grant Shapps has announced an independent review into the £55bn HS2 project.
Led by former HS2 Ltd chairman Douglas Oakervee, the review will consider "whether and how HS2 should proceed", the Department for Transport said.
A final report will be sent to Mr Shapps with "oversight from the PM and Chancellor" by the autumn.
Mr Shapps said: "The prime minister has been clear that transport infrastructure has the potential to drive economic growth, redistribute opportunity and support towns and cities across the UK, but that investments must be subject to continuous assessment of their costs and benefits.
"That's why we are undertaking this independent and rigorous review of HS2.
"Douglas Oakervee and his expert panel will consider all the evidence available, and provide the department with clear advice on the future of the project."
Thousands of British firms will finally be given crucial paperwork that allows them to continue trading with the EU after a no-deal Brexit, but business groups have warned much more must be done to prevent companies going “off the cliff”.
After months of demands from businesses, more than 88,000 VAT-registered companies will be given a registration number in the next two weeks that allows EU customs authorities to identify them.
Without the paperwork, known as an Economic Operator Registration and Identification (EORI) number, UK firms would not be allowed to trade with the EU after 31 October.
More from our business correspondent Ben Chapman:
On the HS2 review, Grant Shapps has told Sky News that a "go or no go" decision on HS2 by the end of the year.
The transport secretary said: "Let's get the facts on the table.
"What I've said to Doug Okervee - who's undertaking this review - and what the prime minister has said too, is, 'Just give us the facts. Go and find out all the information that's out there. Give us exactly where we are up to, really genuinely what it would cost to complete this project, then we will know and we will be in a much better position to make the decision to go or no go by the end of the year."
Mr Shapps said he wanted a "blank sheet of paper" on HS2 and said he had brought in an expert to "get to the bottom of what is the right way forward".
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