Boris Johnson is set to launch a whirlwind round of talks in European Union capitals as he tries to sell his new Brexit proposals to sceptical EU leaders, while also keeping intact an emerging if fragile House of Commons majority for the plan.

The prime minister had been expected to head to Berlin for talks with the German chancellor, Angela Merkel, on Friday. However, scheduling difficulties mean discussions are more likely to begin at the weekend, Downing Street sources said, with trips planned to “several” capitals.

However, no face-to-face talks have yet been confirmed, with Emmanuel Macron’s office saying that the French president was not due to see Johnson at the weekend or next week.

EU parliament: Boris Johnson Brexit plan not remotely acceptable Read more

In the interim, Johnson held phone talks on Friday with the European council president, Donald Tusk, as well as Merkel, the Irish taoiseach, Leo Varadkar, and the European commission president, Jean-Claude Juncker.

Johnson’s chief negotiator, David Frost, has already started what Downing Street termed “technical talks” with his EU counterparts in Brussels, going over the as-yet unpublished draft legal protocol submitted by London.

Formally presenting his plans to the Commons on Thursday, Johnson took a noticeably more conciliatory tone than during a furious debate last week, even as Jeremy Corbyn condemned the proposals as a “Trump-deal Brexit” that would risk regulatory standards.

In contrast, several hardline Brexiters among Tory MPs were cautiously positive about Johnson’s plan. Steve Baker, chair of the European Research Group, told the prime minister: “We now glimpse the possibility of a tolerable deal.”

The PM has the beginnings of a parliamentary majority, with the DUP onboard and a handful of Labour MPs from strongly pro-leave constituencies indicating they could back a deal based on Johnson’s plan. However, it all hinges on whether EU member states are willing.

Among many balancing acts for Johnson in the coming days will be how much room for manoeuvre he has to offer concessions to the EU without dissolving the fragile parliamentary alliance forming around his plan.

Speaking in the Commons, the prime minister hinted that he was not willing to budge especially far. Asked by Alistair Burt, the former Foreign Office minister who was among 21 Tory MPs who lost the party whip for rebelling last month, whether further compromise was likely, Johnson said the UK had already “gone the extra mile”.

Profile Who are the DUP? Show Hide The Democratic Unionist Party (DUP) is a Northern Ireland unionist political party, founded by Ian Paisley in 1971. The party is currently led by Arlene Foster. The DUP achieved their best ever general election performance in 2017, and have 10 of Northern Ireland’s 18 constituency MPs at Westminster, where they are led by Nigel Dodds. Since the election they have been supporting Theresa May’s Conservative government in a confidence-and-supply agreement. The DUP supported leave in the EU referendum, and have repeatedly expressed their concerns over the provisions for an Irish border backstop. This led to them voting against Theresa May’s Withdrawal Agreement with the EU in parliament’s three ‘meaningful votes’. Getting them to back any new Boris Johnson Brexit plan for the island of Ireland is seen as key to him getting parliamentary backing for a deal. Northern Ireland voted to remain in the EU. Devolution and power-sharing in Northern Ireland, where the DUP had held the position of First Minister since 2007, collapsed in January 2017, and has not been restored despite several attempts, most recently in the wake of the murder of journalist Lyra McKee. Martin Belam Photograph: Liam McBurney/PA

“People should be reminded that what the UK has done is already very considerable,” he said. “We have already moved quite some way, and I hope that our friends and partners across the Channel do understand that.”

But at the same time, Downing Street moved away from its earlier briefed line that the proposal was a “final offer” to the EU. A Downing Street spokeswoman hinted at least some flexibility remained possible, reiterating Johnson’s talk about seeking a “broad landing zone”. She added: “The prime minister believes that we have made compromises in this deal but talks have just started today.”

In a noisily received Commons statement, Johnson began by explaining his idea of replacing the Irish backstop insurance policy with a somewhat sketchily outlined new regime of checks.

He insisted there would be no physical customs infrastructure anywhere in Northern Ireland: “The proposals we are putting forward do not involve physical infrastructure at or near the border – or indeed at any other place.”

Johnson said the “driving purpose” of the Irish border proposals was to minimise any disruption, saying that while some new customs checks would happen, none would take place near the border.

The new regime would allow the UK “to take back control of our trade policy and our regulations”, he said, arguing that he had made a considerable compromise, and that it was now up to the EU to do the same.

Responding, Corbyn called Johnson’s ideas “a rehashed version of previously rejected proposals” that were worse than Theresa May’s plan.

Quick guide Why is the Irish border a stumbling block for Brexit? Show Hide Counties and customs Inside the EU, both Ireland and Northern Ireland are part of the single market and customs union so share the same regulations and standards, allowing a soft or invisible border between the two.

Britain’s exit from the EU – taking Northern Ireland with it – risks a return to a hard or policed border. The only way to avoid this post-Brexit is for regulations on both sides to remain more or less the same in key areas including food, animal welfare, medicines and product safety. The 'backstop' in Theresa May's Withdrawal Agreement was intended to address this - stating that if no future trade agreement could be reached between the EU and the UK, then rules and regulations would stay as they are. This has been rejected by Brexit supporters as a 'trap' to keep the UK in the EU's customs union, which would prevent the UK striking its own independent trade deals. There are an estimated 72m road vehicle crossings a year between Northern Ireland and the Republic of Ireland, and about 14% of those crossings are consignments of goods, some of which may cross the border several times before they reach a consumer. Brexit supporters say this can be managed by doing checks on goods away from the border, but critics say it will be difficult to police this without any physical infrastructure like border posts or cameras, which could raise tensions in the divided communities of Ireland.

Interactive: A typical hour in the life of the Irish border Photograph: Design Pics Inc/Design Pics RF

Noting Johnson’s desire to move away from EU standards and push for a US trade accord, the Labour leader said: “Deal or no deal, this government’s agenda is clear. They want a Trump-deal Brexit that would crash our economy and rip away the standards that put a floor under people’s rights at work, that protect our environment and protect our consumers.

Corbyn cited the comments of a series of businesses leaders in Northern Ireland that the checks would badly hamper commerce. He said: “These proposals are nothing more than a cynical attempt by the prime minister to shift the blame for his failure to deliver.”

Corbyn added: “The only people who won’t suffer are the prime minister’s hedge fund donors who are currently betting against the pound and running down our fragile economy. He is doing nothing but seeking to divide and risking this country for his own political gain. An America-first deal with President Trump.”