No 10 believes there is willingness to negotiate as Dublin reiterates importance of backstop

Downing Street believes there has been a shift in the European Union’s willingness to negotiate on the Brexit agreement, which Boris Johnson is expected to press with EU leaders, though optimism in No 10 could be scuppered by a new Irish push to reinforce the importance of the backstop.

The prime minister spoke to the European commission president, Jean-Claude Juncker, later on Tuesday. A Downing Street source said that there was still not a substantive “openness to action” despite a “shift in rhetoric” from EU leaders.

No 10 believes the EU27 must consider whether to approve a new negotiating mandate, something hinted at by Juncker in his call with Johnson. “That would be a sign they are serious about this,” one source said.

Quick guide What is the Brexit ‘backstop’? Show Hide What is the original ‘backstop’ in the withdrawal agreement? Variously described as an insurance policy or safety net, the backstop is a device in the withdrawal agreement intended to ensure that there will not be a hard border between Northern Ireland and the Republic of Ireland, even if no formal deal can be reached on trade and security arrangements. It would mean that if there were no workable agreement on such matters, Northern Ireland would stay in the customs union and much of the single market, guaranteeing a friction-free border with the Republic. This would keep the Good Friday agreement intact. Both the UK and EU signed up to the basic idea in December 2017 as part of the initial Brexit deal, but there have been disagreements since on how it would work. The DUP have objected to it, as it potentially treats Northern Ireland differently from the rest of the UK, creating a customs divide in the Irish Sea, which is anathema to the unionist party. Hardline Tory Eurosceptics also object to it, as they perceive it to be a trap that could potentially lock the UK into the EU’s customs union permanently if the UK & EU cannot seal a free trade agreement. That would prevent the UK from doing its own free trade deals with nations outside the bloc. What was added to May’s withdrawal agreement? Joint interpretative instrument

A legal add-on to the withdrawal agreement was given to Theresa May in January 2019 to try to get her deal through the UK parliament. It gives legal force to a letter from Jean-Claude Juncker and Donald Tusk, the presidents of the commission and council. This stated the EU’s intention to negotiate an alternative to the backstop so it would not be triggered, or, if it was triggered, to get out of it as quickly as possible. Unilateral statement from the UK This set out the British position that, if the backstop were to become permanent and talks on an alternative were going nowhere, the UK believes it would be able to exit the arrangement. Additional language in political declaration This emphasises the urgency felt on both sides to negotiate an alternative to the backstop, and flesh out what a technological fix would look like. However, it failed to persuade the attorney general, Geoffrey Cox, who said that while it ‘reduces the risk’ of the UK being trapped in a backstop indefinitely, it does not remove it. What happens next? Boris Johnson declared the Northern Ireland backstop ‘dead’ during his leadership campaign, and promised to throw it out of any deal he renegotiated with the EU. The EU has repeatedly stated that it will not reopen the withdrawal agreement for renegotiation. Daniel Boffey, Martin Belam and Peter Walker

Johnson will send his chief Brexit adviser, David Frost, to Brussels on Wednesday to continue discussions on alternatives to the backstop with senior EU officials, though No 10 played down the prospect of Frost presenting a concrete proposal for the reopening of negotiations.

Johnson is expected to meet Ireland’s taoiseach, Leo Varadkar, in Dublin early next week, a meeting which a Downing Street source described as “clearly crucial”.

Ireland’s deputy prime minister, Simon Coveney, started a five-city Brexit tour of EU capitals on Tuesday to reinforce the importance of the backstop and Good Friday agreement for Ireland’s economic and social stability.

Play Video 1:21 Boris Johnson insists backstop must be removed for Brexit deal – video

Coveney’s EU offensive on the backstop would appear to counter some claims that the EU is showing new signs of flexibility on the measure after Johnson’s first appearance at a G7 summit, in Biarritz at the weekend.

Speaking in Dublin before the trip and before a meeting with his Norwegian counterpart on Monday night, Coveney spoke of a diplomatic outreach programme to help other nations understand the “unique” impact of Brexit on the island of Ireland.

He also spoke of “the complex constitutional arrangements in Northern Ireland, the experiences of border communities in the past, and the interwoven nature of relationships on the island [that] can be best understood by a visit to the area”.

Coveney is expected to repeat this message in Prague on Tuesday, in Paris on Wednesday, in Helsinki on Thursday and Friday, and in Warsaw on Sunday.

Last week in Dublin, Coveney said it was not the case that the Irish government was refusing to talk to the UK, but said he would not be facilitating the UK in walking away from its commitments in the withdrawal agreement.

Johnson also spoke to the Dutch prime minister, Mark Rutte, by phone on Tuesday. Rutte said he told Johnson that the EU27 was “open to concrete proposals compatible with the withdrawal agreement: respect for the integrity of the single market and no hard border on the Irish isle”.

A Downing Street spokeswoman said there had been “good discussions with EU leaders both last week in France and in Germany, and at the weekend”.

The spokeswoman said Johnson believed there was now a “clear understanding” of the seriousness of the UK’s commitment to leave on 31 October.

“He has also been setting out very clearly the reasons why the backstop is unacceptable to us,” the spokeswoman said. “What is clear is that if there is goodwill on both sides, and a determination to get things done, solutions to the backstop exist and the PM believes they should be discussed.”

Frost is expected to meet officials from the EU chief negotiator Michel Barnier’s taskforce as well as officials from the office of Donald Tusk, the president of the European council.

“The discussions at sherpa level have been going on for a number of weeks now and those will continue this week, both in relation to the visit to Brussels and in the prime minister’s own conversations with leaders which will carry on this week,” a No 10 spokeswoman said.

Securing changes to the backstop may not be enough to convince some of the Conservative hard Brexiters, though Downing Street has in effect ruled out any other changes.

Iain Duncan Smith, who chaired Johnson’s leadership campaign, wrote in the Telegraph on Tuesday that “simply ditching the backstop isn’t enough” and said there were also concerns over the transition period and cooperation on defence and security.

Asked whether Johnson was willing to accept the existing withdrawal agreement if the backstop is removed, the Downing Street spokeswoman said: “We have been clear the changes we are seeking are to the backstop.”