Michel Barnier also doubted whether Britain "fully understood" the consequences of its vote to leave the European Union in March 2019.
He said that Ms May's negotiating position, including abolishing free movement, striking free trade deals and scrapping any role for the European Court of Justice, implied the United Kingdom is leaving both the single market and the customs union.
A Downing Street spokesman said the UK's position was that it would secure "the most frictionless possible trade" between the United Kingdom and the European Union, adding that London's position is clear when asked if Ms May understood the EU's stance.
There's been talk in the highly fluid political scene in Westminster of trying to explore cross-party support for a transitional phase that keeps the United Kingdom in the Single Market and the Customs Union.
Michel Barnier took a tough position on the Brexit negotiations Thursday, warning there will be "negative" consequences no matter what.
"On the European Union side, we made three things very clear: the free movement of persons, goods, services and capital are indivisible". We can not let the single market unravel.
Barnier explained that a "frictionless trade" would only be possible with "the combination of the customs union and the rules of the internal market".
"These consequences are the direct result of the choice made by the United Kingdom, not by the EU".
But Mr Barnier said Mrs May's "red lines" for a future trade relationship meant the United Kingdom was definitely leaving the single market and the customs union.
Despite his ominous tone, Barnier stressed: "There is no punishment for Brexit".
He pointed out that access to the internal market without the customs union, as happens in the European Economic Area, still requires EEA members Norway, Iceland and Liechtenstein to comply with a system of procedures and customs controls; similarly, Turkey's customs agreement with the EU, without access to the internal market, has an implied system of procedures and customs controls as well.
Two weeks ago at the EU Council meeting, European Commission President Jean-Claude Juncker in answer to a question asking if he was clearer now on the United Kingdom position on Brexit snapped back: "no".
Downing Street said the Government did understand the EU's position and was focused on "getting a deal that works for both sides" but acknowledged there were "strong feelings" in Brussels about the result of the Brexit referendum.
The French politician said he was ready for the talks to fail, but said "no deal" would be damaging, especially for Britain, and saw "no reasonable justification" for it. "There is no reason further to worsen the consequences of Brexit".
That equals 2008 for the most by men in the first round during the 50 editions of Wimbledon in the Open era. Djokovic, 30, controlled the match with a 6-3 first set before Kližan retired in the second set.
There is already an inbuilt mechanism of anti-profiteering clause to ensure that GST benefits are passed on to the consumer. Earlier, Revenue Secretary Hasmukh Adhia also busted seven misconceptions regarding GST.
The initiative also says China has recently expanded its facilities on Triton Island to include the construction of a helipad. By sailing within 12 miles of the island, the US conducted what is called a Freedom of Navigation Operation.
According to reports, Nitish Kumar had attacked Congress recently, saying it was not he who changed his ideology, but the party. Politics over Presidential election 2017 started after Kumar extended his support to the NDA candidate Kovind last month.
The Sheriff's Office encourages the public to comply with the evacuation order, which is in place for the safety of the public. The base of the ski resort, which includes hotels and restaurants, has not yet been evacuated.
Toronto has a lot of questions heading into the 2017-18 season, and they could regret not breaking up the team in this offseason. Overall in 2016-17, Redick averaged 15.0 points, 2.2 rebounds and 1.4 assists in 28.2 minutes over 78 games (all as a starter).
Bruce Rauner's veto, ushering in higher income taxes along with a bit of fiscal certainty the state hasn't had since 2015. The state's finances remain a mess, with over $15 billion in overdue bills because of the budget standoff.
Keane was reportedly hopeful of a return to former club Manchester United , but they opted to sign Victor Lindelof from Benfica. The Toffees may also conduct further business with Burnley this summer after reports talks have opened over striker Andre Gray.
"I get exhausted reacting to the president's constant use of Twitter , and I just think he needs to focus on the issues". Crazy Mika ", and claimed she was bleeding from a facelift upon her arrival to Trump's Mar-A-Lago resort at New Year's.
Merkel and Xi meet to lay foundations for G20 talks
In its new manifesto the CDU/CSU refers to the relationship as Germany's most important "partnership" outside Europe. Both leaders have a lot to discuss, from the issues of refugees to the counter-terrorism measures.
J&K will be benefitted most by GST: BJP
PDP MLA Javid Beg reacted sharply to Rashid's statement followed by BJP members demanding Rashid's suspension. He also read out the provisional GST registration numbers of various businesses owned by Rana and his family.
Transfer round-up: Leicester agree Iborra deal
He is likely to compete with Nampalys Mendy for playing time alongside Wilfried Ndidi and Danny Drinkwater . Iborra is a defensive midfielder who is powerful in the air and can control the tempo of a game.
Actress and internet star Stevie Ryan dead at 33
Ryan killed herself in her home. 'I remember waking up and one Little Loca video had like 900 hits and I was like 'Oh, my gosh. The character was obsessively fawn over men on MySpace as well as how many friends she had on the social site.
Trump May Visit Ireland This Month
The White House said Trump has calls scheduled Monday morning with German Chancellor Angela Merkel and Italian Prime Minister Paolo Gentiloni.
Venezuela Oil Price Below $40 for a 2nd Week
Forty-seven percent of the 15 oil market experts say there is more downside risk, but 40 percent say there should not be. The investment bank cited higher-than-expected production from Nigeria , Libya and a swift rebound in US shale output.
Barcelona star Messi weds childhood sweetheart
More than 150 journalists are also expected to cover the event, which will take place at 7pm local time. The pair already have two children together and have known each other since the age of five.
IPhone Turns 10: A Look at the Past, Present and Future
The iPhone 4 received much praise, particularly due to the improvement in style with a body of stainless steel and glass. The folks over at OnLeaks and Tiger Mobiles claim to have gotten their hands on an iPhone 8 dummy unit.
Takata files for bankruptcy, to be bought by US-based firm
In the US, Takata agreed in January to plead guilty to wire fraud for falsifying testing data and reports provided to carmakers. Takata is expected to use $1 billion of the proceeds to cover its settlement of criminal charges with US authorities.