MPs say the Government should accept the supremacy of EU law during a Brexit transition as a “price worth paying” to avoid a no-deal scenario after March 2019.
A report from the Treasury select committee (TSC) said there was now an urgent need for an agreement on transition, and delays risked damaging the economy.
It echoed warnings from the City that the longer arrangements for a transition are delayed, the more businesses would trigger contingency plans such as moving jobs abroad, from early next year.
The report was unanimously agreed by MPs on the cross-party committee with wide-ranging views on Brexit.
Nicky Morgan, chair of the committee, said: “Speed is of the essence.
“Delays to agreements caused by arguments over arcane points of principle could damage the economy.
“The Government should be prepared to accept the terms on which transition is offered by the EU27.”
She said this “may well include accepting EU rules beyond those of the single market and the customs union”.
It was also likely to involve retaining, on a temporary basis, the jurisdiction of the European Court of Justice “and the direct effect and supremacy of EU law”, Ms Morgan added.
“That is a price worth paying for stability and certainty after March 2019.”
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Ms Morgan said the consequences of failing to reach an agreement would be “dramatic and damaging”.
“Many businesses will begin to prepare for a ‘no deal’ outcome – moving jobs and activity, and incurring potentially unnecessary expenditure – early next year,” she said.
“Transitional arrangements must therefore be straightforward enough to negotiate in a matter of weeks.”
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The report was published as Theresa May headed to Brussels for talks with EU leaders, and hours after the Prime Minister suffered her first Commons defeat over Brexit.
Mr Morgan was one of 11 Tory MPs who voted against the Government.