Boris Johnson is expected to make a diplomatic dash to meet Emmanuel Macron in Paris and Angela Merkel in Berlin early next week as he seeks to break the Brexit impasse.

The prime minister, who has yet to leave the UK to meet any of the EU’s leaders since entering Downing Street, will also speak to the Irish prime minister, Leo Varadkar, and Donald Tusk, the European council president, by phone, the Guardian understands.

Tusk said earlier this year that there would be a “special place in hell” for politicians who had championed Brexit “without a sketch of a plan” as to how to make it a success, in what was widely seen at the time as a reference to Johnson.

The flurry of talks come before next weekend’s meeting in Biarritz of the G7, the leaders of the world’s biggest economies, where diplomats expect Johnson to be given a “reality check” as he seeks to lobby the EU to ditch the Irish backstop.

EU diplomats said Johnson would be in Paris on Tuesday and Berlin on Wednesday although the dates are yet to be formally confirmed. UK government sources declined to comment but Whitehall officials played down any hopes of a breakthrough.

As Johnson prepares to make his European tour, a leaked paper from the German government suggested that his insistence that the UK will leave the EU on 31 October with or without a deal had so far failed to prompt a rethink in Brussels and the European capitals.

A document prepared by officials for the German finance minister, Olaf Scholz,before talks in Berlin on Friday with the chancellor of the exchequer, Sajid Javid, stressed the importance of holding out against any renegotiation despite Johnson’s “tough negotiating position”.

The paper makes clear that while the German government does believe that the British government will carry out its threat, the EU still has no intention of returning to the negotiating table on Johnson’s terms.

Leaked to the German newspaper Handelsblatt,, the German officials who drafted the paper warn instead of a “high probability” of a no-deal Brexit on 31 October as it is “currently unforeseeable that prime minister Johnson will change his tough negotiating position”. But its adds that the EU’s preparations for it are “largely complete” and the bloc should hold its nerve.

Following his meeting with the German finance minister, Javid tweeted: “Enjoyed meeting Olaf Scholz in Berlin today. The UK will definitely be leaving the EU on Oct 31st – it is in our mutual interest to do so with a Deal, but we will be ready to leave with No Deal.”

The EU is predicting a “big moment” from Johnson at the forthcoming G7 summit in Biarritz, the leaked paper adds, as the prime minister seeks to pile the pressure on the bloc’s leaders.

“Against this background, it is important from the EU perspective to stick to the previous line” of refusing to renegotiate the withdrawal agreement, the paper says. It adds that “the EU-27’s unity in adhering to the negotiated exit agreement” is vital.

After a meeting between EU diplomats and Johnson’s EU adviser, David Frost, this month, Brussels is also unconvinced that ditching the backstop would deliver a majority in the Commons for the new deal.

Frost is understood to have insisted that a deal was only possible if it included the removal of the backstop, which would keep Northern Ireland in the single market and the whole of the UK in a customs union to avoid a hard border on the island of Ireland. However, he told EU officials that this alone could not guarantee the revised deal being ratified by parliament.

A number of Tory MPs in the 70-strong European Research Group have said they want the entire withdrawal agreement to be ditched.