MPs promised a vote 'if final Brexit deal leads to new treaty with EU'
MPs will get a vote on the final Brexit deal secured by the Government if the agreement results in a new treaty with the European Union, Downing Street has indicated.
Prime Minister Theresa May's official spokeswoman said that the Government would meet its obligations under the 2010 Constitutional Reform and Governance Act, which wrote into law the convention that treaties must be approved by Parliament before ratification except in "exceptional cases".
The clarification came after a Government QC told the High Court that any new treaty agreement with the European Union following Brexit would "very likely" have to be ratified by Parliament.
James Eadie QC said the "view at the moment" was that ratification was likely if the royal prerogative was used to launch withdrawal negotiations under Article 50 of the EU treaties.
Mrs May announced at the Conservative Party conference in Birmingham that she intended to invoke Article 50 by the end of March 2017, setting in train a two-year process leading to Brexit in the spring of 2019.
It remains unclear whether she expects the process to end in one or more treaties setting out the terms of withdrawal or the nature of the UK's future relationship with the remaining 27 member states.
The Prime Minister will attend her first meeting of the European Council on Thursday, where council president Donald Tusk has said she will make a presentation to fellow leaders on "the current state of affairs in the country", but no detailed discussion of Brexit is expected.
Mr Eadie was defending the Prime Minister's decision against a historic legal challenge launched by a group of campaigners, who argue she is in danger of undermining the sovereignty of Parliament.
They say UK citizens face being deprived of statutory rights granted under the European Communities Act 1972, which made EU law part of UK law, without proper scrutiny by Parliament.
Mr Eadie told the court there still would be scrutiny. He argued that a minister using the royal prerogative to trigger Article 50 without prior parliamentary approval would only be "firing the starting gun" for the Brexit process and it would not in itself change any common law or statutory right enjoyed by citizens.
"Any such changes are a matter for future negotiations, Parliamentary scrutiny, and implementation by legislation," he said.
And he added that scrutiny was likely to include Parliament having to ratify any new treaty reached with the EU during the Article 50 process.
The QC said: "The Government view at the moment it that it is very likely that any such agreement would be subject to ratification."
But Mr Eadie stressed he could not go further than "likely" and say it was a certainty.
Lord Chief Justice Lord Thomas, Master of the Rolls Sir Terence Etherton and Lord Justice Sales reserved their decision on the legal challenge at the end of a three-day hearing, promising to give their judgment "as quickly as possible".