Irish prime minister Leo Varadkar has said the UK’s new Brexit proposals “do not fully meet the objectives of the backstop” following a phone call with Boris Johnson.

But despite the pessimism, a statement from the Irish government said the Taoiseach would study the plans further and consult with other EU leaders.

The backstop is an insurance policy to maintain an invisible border between Northern Ireland and Ireland negotiated by Theresa May, which would have kept either the whole UK or the province in a customs union with the EU, restricting the ability to sign free-trade deals around the world. 

Johnson’s new plan envisages the entire UK leaving the customs union, but with Northern Ireland staying aligned to EU rules on goods as long as the Stormont assembly and executive agree every four years.

This would create the need for customs checks on goods travelling between Northern Ireland and Ireland, and a need for regulatory checks on goods travelling between Great Britain and Northern Ireland.

The PM insisted that customs checks could take place away from the Irish border.

“The Taoiseach said the proposals do not fully meet the agreed objectives of the backstop,” the statement said.

“However, he indicated that he would study them in further detail, and would consult with the EU institutions, including the Task Force and our EU partners.

“The Taoiseach expects to speak with European Council President Donald Tusk, European Commission President Jean-Claude Juncker, and with other EU heads of government over the coming days.

“This will include the Swedish and Danish prime ministers, with whom the Taoiseach has bilateral meetings on Thursday and Friday in their capitals.

“The Taoiseach said he wants to see a deal agreed and ratified, and will continue to work in unity with our EU partners to this end.

“The Taoiseach and the Prime Minister agreed they would speak again next week.”

The Prime Minister submitted a letter to European Commission president Jean-Claude Juncker on Wednesday afternoon containing the UK’s proposals.

Johnson said the plan had five elements:

– A commitment to a solution compatible with the Good Friday Agreement;

– Confirmation of support for long-standing areas of UK-Ireland collaboration including the Common Travel Area and north-south co-operation;

– The potential creation of an all-Ireland regulatory zone covering all goods including agri-food;

– The consent of those affected by that all-Ireland zone with the Northern Ireland Executive and Assembly given the chance to endorse the plan before it comes into effect and then every four years;

– Northern Ireland will be fully part of the UK customs territory and outside the EU’s customs union.

Johnson claimed the plan was “entirely compatible with maintaining an open border in Northern Ireland”.