Speaking in Dublin, the EU's chief Brexit negotiator Michel Barnier warned against any attempts by the UK to pick apart the single market, and said its benefits were only possible because of a "common ecosystem of rules," uk.finance.yahoo.com reported.
"As each member state knows well, enjoying the benefits of the single market is only possible with a common ecosystem of rules [...] and the jurisdiction of a common court," he told an audience at the Institute of International and European Affairs in Dublin.
"In this period where the EU has faced so many challenges, it becomes even more important to consolidate and strengthen the single market. Our single market is the foundation of our unity," he later added.
Barnier also emphasized that the EU's "backstop" proposal to keep Northern Ireland within the single market for goods could not be rolled out to the rest of the UK, which is the arrangement Theresa May will reportedly seek.
"The [backstop] solution we have proposed is specific to unique circumstances of Ireland and Northern Ireland," he said.
"We have made an exception to our rules [...] to address very specific challenges to Ireland and Northern Ireland," he said.
Barnier's comments came as May assembled her cabinet for crunch talks which could define the shape of Brexit.
As the EU’s chief Brexit negotiator warned that time was running out, May convened what were expected to be marathon talks on Friday at her Chequers country residence to agree on a plan for Britain’s future outside the EU, Reuters reported.
After months of reticence, May was forced to thrash out an agreement with her divided cabinet of ministers to push on with all-but-stalled talks and ease growing concerns about a no-deal Brexit.
Asked Friday morning whether the prime minister was expecting any resignations, her official spokeswoman replied "let's just see what happens."
The lack of progress has frustrated European leaders, who are stepping up preparations in case there is no agreement at all, and businesses who are being increasingly vocal about the risks to jobs and investment.