Michel Barnier has warned there is “not a minute to lose” in efforts to achieve a Brexit deal as he prepared for talks with Theresa May.
The European Union’s chief Brexit negotiator was travelling to London as Downing Street insisted the UK would not remain in a customs union with the EU after leaving the bloc.
Mr Barnier, who will have talks with Mrs May and Brexit Secretary David Davis, said there was “much work” to be done to achieve a deal and it was time to “accelerate” diplomatic efforts.
“My feeling is we have not a minute to lose because we want to achieve a deal,” he told reporters.
“There is so much work so we have decided for this reason to accelerate all the contacts.”
Mr Barnier said he would “respect the red lines” set out by Mrs May, but the UK must also “respect the rules of the union”.
The intervention by Number 10 to “categorically” state the UK would not be part of a customs union came after apparent confusion at the top of government over the approach to the issue.
Confirmation of the government’s approach may placate Tory MPs and ministers who are keen for a Brexit arrangement which allows the UK to strike trade deals around the world – something which a customs union could have prevented.
But business leaders have urged the government to remain in a customs union, and Tory Brexit rebel Anna Soubry urged Number 10 to “do the maths” and listen to company bosses.
She claimed the Hard Brexit European Research Group (ERG) of Tory MPs, led by Jacob Rees-Mogg, had a “deeply unattractive” plan which involved leaving the customs union “to chase unicorn trade deals” at the expense of existing relations with the EU.
Downing Street sought to draw a line after days of sometimes conflicting messages from ministers about the approach to future customs arrangements.
Mrs May’s official spokesman said the government had set out its position in a paper published in August, which stated that the UK was leaving the EU customs union but was exploring the possible alternatives of a “highly streamlined customs partnership” or a “new customs arrangement” with the EU.
The spokesman said the August paper acknowledged that the option of a customs partnership would be “challenging” to implement.
“We will be leaving the European Union and the customs union and it is not the government’s policy to be members of the customs union,” he said.
He added: “The key point is that we need to be able to strike our own trade deals.
“We have said that we want to be free to negotiate and sign trade deals during the implementation period and then bring them into force once we leave.”
The spokesman said that Mrs May would join Mr Barnier and Mr Davis for around 20 minutes before leaving them to have lunch together with Brexit negotiator Olly Robbins and the UK’s ambassador to the EU Sir Tim Barrow.
The talks would primarily deal with the nature of the transition period, but might touch on the future UK/EU relationship, he said.
Mrs May’s Brexit “war cabinet” is due to meet on Wednesday and Thursday to continue discussions on the “end state” relationship which the UK will seek with its former EU partners.
High on the agenda is likely to be the row over the status of EU nationals who come to the UK during the transition period of around two years after the date of Brexit in March 2019.
Mrs May has made clear she will resist EU proposals for these people to be entitled to settle permanently in the UK.
Her spokesman said: “The point the PM made is that people who arrive after we have left the EU will arrive with different expectations and understandings of the way forward – and they will therefore be treated differently.
“Precisely what that looks like is a matter for negotiations over the next few weeks. People will be free to live and work here. The issue is the rights they accrue as a result.”
The chairman of the Commons Exiting the EU Committee, Hilary Benn, said further detail was still needed from ministers if the terms of a future deal with Brussels are to be agreed by October as hoped.
“I wish it was clarity but I don’t think it is. I think the government is in a state of open disagreement, the prime minister has been immobilised,” the Labour MP told BBC Radio 4’s Today.
It was a “profound mistake” to leave a customs union, he said, and it would create the need for checks at the Northern Irish border.