Sir Vince Cable claimed “if” Brexit day ever happens it will be “a day of mourning” during a shock attack in the House of Commons.
It comes after the Prime Minister was dealt a series of blows following the resignations of former Brexit Secretary David Davis and former Foreign Secretary Boris Johnson, over Theresa May’s Brexit plans.
Speaking in the Commons, Mr Cable said: “The very striking things about the comments that resigning members of the government have made is the way in which they are managing to poison their own well.
“It’s extraordinary the extent to which the phrase betrayal is entering the narrative.
“And we risk getting to a point in a few months time if Brexit happens, and I think it is an if rather than a when, in which one side here, the many people who regard Brexit as a disastrous error, will be pointing out the many problems that arise from it.
“And those who have devoted their lives to fight for Brexit will be arguing that it is a disaster because it is a betrayal.
“If Brexit day ever happens, it will be a day of mourning, it is very difficult to see where the positive story is going to come from to help the country turn over a new leaf.”
He added: “All of this is being discussed in a Westminster bubble, and we will be frequently reminded that there is such a thing as the popular will.
“But the popular will, as manifested in surveys of public opinion, suggest that at present about 70 percent of the public judge that the Government is handling the Brexit negotiations badly, and it’s been on a declining trend pretty much for the last year.
“A lot of that disillusion has to do with the way in which members of the Government have themselves been conducting themselves.
“And over the last few days, there is a treasure trove of quotations from senior members of the Government about what they really think about the Government’s negotiating position.”
Mrs May was forced to reshuffle roles in her cabinet following a series of resignations, including David Davis and Boris Johnson after the Priem Minister had agreed to a position on her Brexit model at Chequers last Friday.
Former Health Secretary Jeremy Hunt was reassigned to the role of Foreign Secretary and Dominic Raab became the Brexit Secretary.
The Prime set out her Brexit model in the House of Commons on Monday. She said: “On Friday at Chequers our cabinet agreed a comprehensive and ambitious proposal that provides a responsible and credible basis for regressing negotiations with the EU towards a new relationship after we leave on the 29 March next year.
“It is a proposal that will take back control of our borders, our money and our laws. But do so in a way that protects jobs, allows us to strike new trade deals through an independent trade policy, and keeps people safe and our union together.”
Former Foreign Secretary Mr Johnson claimed his Brexit dream ”is dying” in his scathing resignation letter.
Mr Johnson wrote: “Brexit should be about opportunity and hope. It should be a chance to do things differently, to be more nimble and dynamic, and to maximise the particular advantages of the UK being an open, outward-looking global economy.
“That dream is dying, suffocated by needless self-doubt.”