NEW YORK (Reuters) - British Prime Minister Boris Johnson cautioned on Monday that there would be no Brexit breakthrough at talks with European leaders in New York as gaps remained, but said significant progress had been made on striking a deal.

FILE PHOTO: British Prime Minister Boris Johnson leaves after a meeting with Luxembourg's Prime Minister Xavier Bettel in Luxembourg, September 16, 2019. REUTERS/Yves Herman

Three years after the United Kingdom voted in a referendum to leave the European Union, hopes of an emerging deal to ease the transition were stoked when Johnson said that the shape of an accord was emerging, and European Commission President Juncker said an agreement was possible.

But the two sides remain split over London’s desire to remove the Irish “backstop” - an insurance policy to prevent a return of border controls on the island of Ireland - from the divorce deal struck by Johnson’s predecessor Theresa May.

EU sources said no proper alternative for the border between Northern Ireland, a British province, and Ireland that ensures the integrity of the EU single market and customs union has been proposed yet by London, so no breakthrough is on the cards.

Johnson, who has vowed to deliver Brexit on Oct. 31 with or without a deal, will meet EU leaders on the sidelines of the United Nations General Assembly in New York, including Germany’s Angela Merkel and Irish Prime Minister Leo Varadkar.

He will also discuss progress on reaching a Brexit deal with European Council President Donald Tusk.

“I would caution you all not to think that this is going to be the moment,” Johnson told reporters on the plane to New York. “I don’t wish to elevate excessively the belief that there will be a New York breakthrough.”

He said a “great deal” of progress had been made since he took office in July, citing what he described as EU leaders’ acknowledgment that the Withdrawal Agreement they reached with May needed to be changed. But Johnson added that there were “clearly still gaps and still difficulties”.

An EU official said last week talks were going nowhere.

“We don’t even know how to read what they are doing. If they are genuinely trying to open a negotiation, it would take them another 6-9 months to get to something. Or is it just tactical, and aimed at avoiding the blame?” the official said.

With the outcome of the marathon Brexit process still uncertain, the opposition Labour Party will vote to decide its strategy on Monday, leader Jeremy Corbyn heading for a showdown with the widely pro-EU party membership over whether Labour should endorse a policy of remaining in the bloc.

BREXIT IN PLAY?

Johnson wants to remove the so-called backstop, which aims to avoid the return of controls along what would be Britain’s only land border with the EU by having London follow the bloc’s rules on trade, state aid, labour and environmental standards.

Ireland is crucial to any Brexit solution. Unless the Irish border backstop is removed or amended, Johnson will not be able to win parliamentary approval - but Ireland and the EU are loath to sign a deal without a solution to the border.

An open border is seen as vital to trade on the island of Ireland but to preserving the 1998 Good Friday accord that ended decades of sectarian violence in Northern Ireland.

Britain last week shared technical documents with Brussels setting out its ideas for dealing with the backstop, although these were not the formal legal proposals Brussels has sought.

Johnson has said he wants to secure an amended deal at an EU summit on Oct. 17-18, and said “a large number of the important players”, including Britain, Germany, France and Ireland, wanted to reach an agreement.

“We have seen interest in the idea of treating the island of Ireland as a single zone for sanitary and phytosanitary purposes that is also encouraging,” he said. “However there are clearly still gaps and still difficulties.”

Johnson said it was important the United Kingdom “whole and entire” was able to break away from EU law in future.

“The problem with ... the current backstop is that it would prevent the UK from diverging over a huge range of industrial standards and others,” he said. “We may want to regulate differently but clearly there is also a strong incentive to keep goods moving fluidly and we think we can do both.”

Johnson’s government, worried the backstop will trap Britain in the EU’s orbit for years to come, wants to remove it and find a solution before December 2020, when a planned transition period ends.