Britain remains a long wayfrom agreeing a final Brexit deal and the next few days will be critical if itis to agree departure terms with the European Union, a Downing Street sourcesaid on Saturday.
Negotiators for Britain andthe EU have entered intense talks over the weekend to see if they can break theBrexit impasse before a crucial summit next week and a deadline for Britain toleave the bloc on Oct. 31.
News of progress in thetalks sent financial markets surging on Friday after Johnson and his Irishcounterpart Leo Varadkar identified a pathway to a deal following months ofacrimony.
But on Saturday the deputyleader of the Northern Irish party which holds a key role in the talkssignalled his concern about the mooted proposal and the Downing Street sourcesaid Britain remained ready to leave without a deal if needed.
"We've always wanted adeal," the person said, on condition of anonymity. "It is good to seeprogress, but we will wait to see if this is a genuine breakthrough.
"We are a long wayfrom a final deal and the weekend and next week remain critical to leaving witha deal on Oct. 31. We remain prepared to leave without a deal on Oct. 31."
The Sunday Times newspaperreported that Johnson, the face of Britain's 2016 campaign to leave the EU, wasnow "desperate" to secure a deal after security chiefs warned thatleaving in a disorderly manner could inflame tensions in Northern Ireland.
Ireland has proved thetoughest nut to crack in the Brexit talks, specifically how to prevent theBritish province of Northern Ireland becoming a backdoor into the EU's marketswithout having border controls.
Ireland fears controls onthe 500-km (300-mile) border with Northern Ireland would undermine the 1998Good Friday Agreement which ended three decades of sectarian and politicalconflict that killed more than 3,600 people.
Johnson is likely to talkto senior EU leaders on Monday to reassess the situation, the sourcesaid.