Keir Starmer has said he would have already struck a Brexit trade deal with Brussels and he told Boris Johnson to pull his finger out and strike an agreement with the EU.
The Labour leader has said that the most important thing for the PM to focus on is striking a deal.
Speaking on LBC's Call Keir Mr Starmer was asked how he would have handled things differently than Mr Johnson.
He said: “I think we would have a got a deal by now.
“We would negotiate on a good deal in the interest of our country.”
Pushed on the details, Mr Starmer admitted he didn't have the level of detail open to British negotiators but insisted a deal was there for the taking.
Asked if he would agree to EU demands for 10 years of access to British waters, Mr Starmer said he “wasn’t in the room” but that striking a deal was essential to British interests.
“We want the Government, we want David Frost and his team to succeed,” he told LBC.
Mr Starmer suggested that he would willing to see future UK regulation share a path with the EU.
He said: “We need to recognise that in any trade deal you’ve got to agree standards and then a mechanism on how to manage that.”
It comes after it emerged that hat Brexit talks could drag on past Christmas - with both sides under pressure to avoid the economic chaos of not striking a functioning trade dea.
EU rules in the UK will come crashing to an end on December 31 if there’s no trade pact.
Mr Johnson and European Commission President Ursula von der Leyen issued a more optimistic statement yesterday as they decided not to call off the talks.
The PM yesterday warned a no-deal Brexit was now the “most likely” outcome - but insisted officials will go the “extra mile” to try to thrash out a pact.
Unusually neither side has set a deadline for the new round of talks, which gets under way today.
And a government source indicated new talks would go on for days at least, not hours.
Even if a Brexit deal is agreed before Christmas Day in 10 days’ time, it would still need to be ratified by the UK and European Parliaments before December 31.
MPs have, highly unusually, still not been told their recess dates for the festive break.
And The Sun reported last week that plans have already been drawn up for Parliament to possibly sit over Christmas.
Business Secretary Alok Sharma today insisted “we don’t want to walk away from talks”.
Asked if they could go on until New Year’s Eve, he told BBC Breakfast: “Obviously we’ve always said the transition period ends at the end of December and we will not be continuing discussions beyond that.
“And of course any deal that we have would then have to go through Parliament so that really would be cutting it quite fine.
“But it’s also the case - and we’ve seen this in the past - that Parliament can move very quickly, can be very agile when it needs to be.”
Former chief whip Mark Harper, speaking to BBC Radio 4's Westminster Hour, said: “Many of us are fully anticipating it's entirely possible we might be returning to Parliament between Christmas and new year to scrutinise this and vote it through if a deal is done."
EU chief negotiator Michel Barnier was briefing diplomats from the 27 member states this morning as talks resumed.
The two main hold-ups are on fishing access and quotas, and the “level playing field” of how far the UK follows EU rules in future.
Ms von der Leyen has offered an olive branch, saying the UK will not have to automatically follow all future EU rules on areas like the environment in future.
