Downing Street has dismissed reports that a Brexit deal is close, saying any suggestion of an imminent agreement should be taken with "a bucket of salt".
It came after claims that Michel Barnier, the EU's chief negotiator, had told EU ministers that "the parameters of a possible agreement are very largely defined".
Earlier, Downing Street revealed that officials had been locked in negotiations until 2.45am on Monday morning as Theresa May scrambles to secure an agreement this week.
In his weekly Telegraph column, the former foreign secretary said the prime minister's plan would reduce the UK to the status of a colony and see the country "remain in captivity".
He wrote:
"The awful truth is that even if the Cabinet mutinies - as they ought - it will make little difference.
"Even if we agree with the EU that the UK must have a unilateral break clause, so that we can go our own sweet way at a time of our own choosing, it is irrelevant because the programme and ambition of the Government is to remain in captivity, to stay in our cell, even if we are given the theoretical key to escape."

Brexit timetable in turmoil as Theresa May is forced to cancel planned cabinet meeting to approve her deal
Hopes fading for an EU sign off this month amid fierce resistance to the PM’s proposals in her cabinet and in BrusselsFrance's Europe minister, Nathalie Loiseau, has said any proposal that would give the UK the right to unilaterally withdraw from a customs backstop is unacceptable to the EU.
Speaking as she arrived in Brussels for a meeting with Michel Barnier and other EU foreign ministers, she said:
"The ball is in the British court. It is a question of a British political decision."
"I have no crystal ball unfortunately. We are determined, we are committed to find a good deal. We know that it is better than a no-deal."
She added:
"If you have any sort of temporary arrangement, this needs to be a bilateral decision from the EU27 and the UK at the same time, and we have to know at that moment what sort of solution there is for the Irish border."

Spain's prime minister calls for a second Brexit referendum
Premier says UK heading down path of 'self-absorption'"Michel Barnier explained that intense negotiating efforts continue, but an agreement has not been reached yet.
"Some key issues remain under discussion, in particular a solution to avoid a hard border between Ireland and Northern Ireland.
"During the meeting, ministers however also recalled the need to continue the work at all levels on preparations for every possible scenario."

Brexit 'can be stopped', Labour's Keir Starmer says
Labour's official policy is to leave all options on the table, including the prospect of a second referendum"We have made good progress in the negotiations in relation to the withdrawal agreement but there are substantial issues still to be overcome in relation to the Northern Irish backstop.
"That remains the case. The talks are ongoing."
"We want to make to progress as quickly as possible in these negotiations but we have also said that cannot be at any cost. That remains the position."

Lord Lester faces suspension from House of Lords for nearly four years over sexual harassment claim
'If the suspension is agreed by the House of Lords it will be the longest suspension of a Member of either House since at least the end of World War II'"After two years of negotiations, none of the major issues are resolved.
"If nothing changes, we will be an even more divided Britain. More divided than during the three-day week of the 70s, more divided than during the miners strikes of the 80s, more divided than the poll tax disagreements of the early 90s, more divided than after the Iraq War."
"I for one have always said that I think there will be a second referendum. I believe that, in the end, the situation will have been seen to have changed since 2016 and that the people should, in the end, have the final say."
"We must get away from the short-termism that has bedevilled everything the government has done in the last few years on this, and take a long-term view."

Hopes fade for emergency EU summit as No10 admits 'substantial issues' stand in way of Brexit deal
EU member states claim that a Brexit deal hinges on agreement of Theresa May's cabinet, rather than difficulties with Brussels."These allegations are completely untrue. I produced evidence which clearly demonstrated that what I was said to have done 12 years ago did not happen.
"Independent counsel who previously advised the committee on its procedures provided an advice which concluded that the investigation was flawed. I regret the committee's conclusions in the light of these materials.
"There has to be a fair process for investigating sexual harassment claims in Parliament. Parliament is supposed to be a bastion of the rule of law but has ignored calls to reform this procedure properly for 20 years.
"I hope to be judged by my work over decades for gender equality, race relations and free speech."
“Even through this weekend [the negotiating teams] worked tirelessly to reach an agreement. As of this moment, this agreement is still not reached. As in any negotiation, the final stretch is always the most difficult.”
He added:
“On the basis of our common efforts, the parameters of a possible agreement are very largely defined. On the British side, the cabinet will meet tomorrow [Tuesday] to examine these parameters. We are at an extremely sensitive moment. The smallest public comment from my side could be exploited by those who want the negotiation to fail.”
“This is a calculated deceit on the British people. I challenge the government to come clean on the cost of Brexit. The reason they can’t look us in the eye, it’s because they know this will leave us worse off and with less control. It’s a gross abuse of civil service impartiality.”
The Independent has launched its #FinalSay campaign to demand that voters are given a voice on the final Brexit deal.
Sign our petition here