The European Commission president, Jean Claude Juncker has criticised the UK's Brexit negotiations, saying none of the papers provided so far are satisfactory.
UK Prime Minister Theresa May has openly stated that she would take the country out of the European Union even if she fails to strike a deal with the bloc, but Labour leader Jeremy Corbyn has asked for a softer approach that involves retaining Britain's access to the EU's tariff-free single market.
"Mr Juncker says it's "crystal clear" that we can't talk about the future relationship before solving divorce issues, but this is a decision to be taken by the European Union 27, not the commission", a government source claimed.
Yesterday Mrs May confirmed that Britain hoped to be able to copy and paste trade deals the European Union has with other countries after Brexit.
The EU wants to settle Britain's so-called Brexit divorce bill before talks begin on the new trade relationship with the UK.
Financial newswire Bloomberg reported that the United Kingdom has asked for more Brexit negotiating sessions, as the latest round of talks showed little sign of progress amid criticism from each side.
The spokesman also said it is now time to move on to the next port of discussion.
The EU's chief negotiator Michel Barnier was to meet his British counterpart David Davis late afternoon for a first exchange, followed by three days of talks and a joint press conference.
Any final deal will have to be approved by the European Parliament. On Monday, the head of the Federation of German Industries - an influential group in the EU's biggest economy - said that "appreciable progress can hardly be expected".
No 10 rejected Juncker's comments - and doubled down on Davis's insistence that talks on a trade deal should take place alongside settling withdrawal issues, including the size of any financial settlement.
"I would like to be clear that I did read with the requisite attention all the papers produced by Her Majesty's government; I find none of them truly satisfactory". He added, "they have made it quite clear that we can not honor the decision of the referendum if we remain in the customs union and the single market".
Starmer said: "There's a growing consensus on both sides of the Channel that it's extremely unlikely that a bespoke transitional period can be negotiated, agreed and implemented by March 2019".