MPs across Parliament have angrily accused ministers of ignoring the will of the House after they said they would only release a "full reasoned political statement" on the legal position.
"In nine days time, Parliament has got to take probably the most important decision it has taken for a generation and it's obviously important that we know the full legal implications of what the Prime Minister wants us to sign up to", said Mr. Starmer.
Former Brexit secretary Dominic Raab said the backstop will last "until it is superseded by the treaty setting out our future relationship, unless the European Union allows us to exit".
United Kingdom lawmakers are set to begin debating May's Brexit package this week, but the signs don't look promising for the prime minister.
Merkel lauds G20 agreement on need for reform of world trade
The plane, which was operated by the German air force, had a communications systems failure, according to a military spokesman. Merkel was still waiting for a replacement plane to take her to Buenos Aires for the G20 summit.
Back in Britain, the premier was hit by the resignation of Science Minister Sam Gyimah, who slammed her Brexit deal in a lengthy Facebook post, while Culture Secretary Jeremy Wright appeared to go off-message, suggesting that if Parliament rejects May's agreement with the European Union, it could lead to a second referendum.
The proposed amendment would hand power to lawmakers if her plan is rejected in the House of Commons - and could potentially provide a legislative pathway for a referendum.
"I think there's a sort of democratic duty on politicians, having had that referendum, having told people it is their choice".
Downing Street has not responded to claims by the Daily Telegraph that a letter from Mrs May's chief Brexit adviser, Olly Robbins, warned her it was a "bad outcome" with no legal "guarantee" Britain would be able to exit the mechanism.
Putin and Saudi Crown Prince 'high five' at G20 photo op
Mrs May had a meeting with the prince on the first day of the G20 summit of world leaders in Buenos Aires , Argentina. MBS is expected to meet with just a few leaders at the summit in Buenos Aires , including Putin .
Britain's opposition Labour Party ramped up the pressure on Prime Minister Theresa May Sunday, saying it will call a no-confidence vote if Parliament rejects her Brexit deal on December 11. That's something May has said won't happen on her watch.
The two-part agreement includes the legally binding terms of the UK's departure and an ambitious but vague declaration about future relations between the two sides.
Over 100 Tory MPs are reportedly likely vote against the withdrawal agreement next week, according to lists compiled by Buzzfeed News and the Guardian.
After months of negotiations, the Brexit deal has been thrashed out.
Meanwhile, as campaigners continue to push for a further referendum, an e-petition urging the government to rule that option out, will be debated by MPs from 16:30 GMT.
Trump to miss opportunity to discuss controversial issues with Putin: Russian lawmaker
The president's stated reason for skipping a Putin meeting - the crisis in Ukraine - is a legitimate one. Trump's tweet appeared shortly after he boarded Air Force One to depart for the summit.