Britain wants an “impossible” Brexit deal where it retains the benefits of EU membership despite leaving the bloc, the EU’s chief negotiator has said.

Michel Barnier said the consequences of leaving the EU did not appear to have been considered in “sufficient depth” in the UK and that he saw a certain “nostalgia” in British negotiating positions for the bloc’s benefits.

Mr Barnier told reporters in Brussels that “decisive progress” had not been made on “principal subjects”, though Brexit Secretary David Davis struck a more positive tone, saying the “high-stress week” of negotiations had delivered “some concrete progress”.

At a press conference to mark the end of the latest round of talks, Mr Barnier said: “The UK wants to take back control, it wants to set its own standards and regulations, but it also wants to have these standards recognised automatically in the EU, that is what the UK position papers say. This is simply impossible: you cannot be outside the single market and shape its legal order.”

One British position paper about data protection rules released last week suggested that the UK could still shape EU regulations after Brexit, and have its own regulations automatically recognised by the EU on a preferential basis.

The EU negotiator continued: “As I’ve said on a number of occasions there are a lot of consequences for citizens, for consumers, for businesses.

“Perhaps not all have been debated in sufficient depth in the United Kingdom but now is the time to explain what no longer being a member of the EU and the single market entails and what no longer being a member of the single market entails.

“When I read some of the papers David [Davis] has sent me on behalf of the British Government, in some proposals I see a sort of nostalgia in the form of specific requests that would amount to continuing to enjoy the benefits of the EU and the single market without being a part of it.

“As I said earlier, Brexit means Brexit. Leaving the single market means leaving the single market. If that is what has been decided, there will be consequences.”

But Mr Davis hit back: “I wouldn’t confuse a belief in the free market for nostalgia.”

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The Brexit Secretary said there would be further position papers from the UK Government released in the coming weeks. The Government has been criticised for not releasing a position paper on the Brexit divorce bill, the biggest stumbling block of negotiations so far.

“The third round of talks have been productive and have been an important building block and key stepping stone for talks to come,” Mr Davis told reporters.

“I’ve said from the beginning of this process, some parts will be turbulent, hard, and we’ve seen that, because there are differences of view.”

Brexit: the deciders Show all 8 1 /8 Brexit: the deciders Brexit: the deciders European Union's chief Brexit negotiator, Michel Barnier Getty Brexit: the deciders French President Emmanuel Macron Getty Brexit: the deciders German Chancellor Angela Merkel Reuters Brexit: the deciders Commission President Jean-Claude Juncker EPA Brexit: the deciders The European Parliament's chief Brexit negotiator Guy Verhofstadt Getty Brexit: the deciders Britain's Prime Minister Theresa May Getty Images Brexit: the deciders Britain's Chancellor of the Exchequer, Philip Hammond PA Brexit: the deciders After the first and second appointed Brexit secretaries resigned (David Davis and Dominic Raab respectively), Stephen Barclay is currently heading up the position PA

UK officials also seized on Mr Barnier’s comments that he was sticking to his mandate set by the European Council “meticulously”. People familiar with the British negotiating position say the mandate set by the EU27 member states is too narrow and inflexible to allow a good deal to be reached.