UK 'must be ready to vote against EU measures'
Ministers must continue to scrutinise - and be prepared to vote against - new EU measures while it remains a member of the EU, a committee of MPs has said.
EU proposals should be considered by the UK both as an EU member state, and in terms of their Brexit implications, the European Scrutiny Committee said.
Policies would affect the UK up to, and in some cases after, Brexit, it said.
The government has said it "will continue to negotiate, implement and apply EU legislation" until Brexit.
Prime Minister Theresa May formally began the Brexit process last week when she triggered Article 50 of the Lisbon Treaty, meaning that, unless the UK and the 27 remaining EU member states agree to extend the deadline for talks, the UK will leave on 29 March 2019.
Until then, the committee points out, the UK continues to take its place in negotiations on EU legislation at the European Council and in the Council of Ministers.
Brexit Secretary David Davis has pledged to "exercise our influence over what we think is the best interests of the European Union until the moment we leave".
But the committee heard from the UK's former ambassador to the EU, Sir Ivan Rogers, who said, in the six months after the EU Referendum, he "saw a diminution of Whitehall attention and effort on day-to-day dossiers".
He also suggested that other EU member states may already be preparing for life after Brexit as new legislation goes through: "Others are, frankly, looking at opportunities in the next couple of years to land things in directives and regulation that they know are going to cause us difficulty."
The committee said all departments should consider new EU proposals both from the perspective of the UK as a member state and in terms of their Brexit implications. It said the government must give "proper priority to negotiations on existing dossiers" as well as "minimising the risk that changes to current EU law may disadvantage the UK after Brexit".
"The government may consider that there will be occasions when it feels it should vote against proposals it considers to be against the national interest, rather than allowing agreement by consensus," the committee said.
Commons Leader David Lidington warned that "an approach to negotiations on dossiers that enabled others to paint us as wreckers would not be helpful in the exit negotiations". The committee said while they would not want the UK to be seen as a "wrecker" it was "entitled to oppose [European] Commission proposals and to make their views known".
"We consider that it may now be appropriate for the government to be firm in its attitude to proposals it considers misguided and to be readier to vote against such proposals if it does not manage to negotiate satisfactory changes."
While recognising "clearly considerable" pressures in Whitehall and UKRep - the UK permanent representation to the EU - the committee raised concerns that "departments may not have been giving sufficient priority to negotiations on new and existing EU dossiers" which would continue to affect UK law until Brexit - and in areas like trade or EU energy policy, afterwards.
"It cannot start from the assumption that EU policy and legal frameworks are fixed. Rather than driving away from a fixed petrol pump, Brexit is analogous to disengaging from mid-air refuelling. Both parties are moving; the challenge is to separate them without either losing momentum."
Shadow Brexit minister Paul Blomfield accused the government of "failing to grasp and prepare for the complexity of the Brexit negotiations" adding: "The government is treating EU law and policy as fixed, when the committee is right to say it's evolving."
A government spokesman said: "We have been clear that we are a full member of the European Union until the day we leave and so we will continue to respect the rights and obligations of EU membership and engage with day-to-day EU business. "That is why ministers from across government have regularly represented the UK at EU Council meetings since last year's referendum."