LONDON — A Brexit deal under discussion by European leaders would be worse for the U.K. than remaining in E.U., according to a lawmaker who helped to draft it.

Dominic Raab, who quit as Britain’s Brexit secretary earlier this month, said the proposed divorce settlement was unlikely to be approved by lawmakers, raising the stakes on all sides in the acrimonious and chaotic process.

"We will, I think, inevitably see parliament vote this deal down,” he told BBC Radio 4.

Former Brexit Secretary @DominicRaab says Theresa May's proposed EU deal would be worse than staying in the EU on current terms. "We'd effectively be bound by the same rules but without the control or voice over them" #r4today — BBC Radio 4 Today (@BBCr4today) November 23, 2018

Raab's comments add weight to bipartisan calls for a second referendum on Brexit now that the possible outcomes are clearer to voters. Prime Minister Theresa May has ruled out another public vote.

Britons voted narrowly to leave the E.U. in a June 2016 referendum, a shock result that plunged the world’s fifth-largest economy into a political crisis.

The country is due to leave the 28-nation trading bloc in 126 days’ time on March 29, but negotiations over the terms of its departure have been plagued by disagreements on everything from borders and customs to shared laws and regulations.

Dominic Raab wants no part of the deal he helped to negotiate. Jeff Overs/BBC / Reuters

May and her E.U. counterparts are discussing a 585-page withdrawal agreement and a less detailed seven-page declaration on future relations, which negotiators hope will be rubber-stamped at a summit this weekend. She declared Thursday that a solution is “within our grasp.”

But the plans have infuriated pro-Brexit lawmakers in May's own Conservative Party, who prefer a clean break with the E.U. and say the divorce deal would leave Britain a vassal state, bound to E.U. rules it has no say in making.

They include Raab, who said Friday: "I'm not going to advocate staying in the E.U. but, if you just presented me terms, this deal or E.U. membership, because we would effectively be bound by the same rules but without the control or voice over them, yes, I think this [deal] would be even worse than that."

Others, including May’s finance minister, say a "no-deal" Brexit — with the U.K. leaving the bloc without reaching any agreement — would cause chaos at border crossings on both sides, crippling trade and supply chains. They say May’s proposed deal is the only way to implement a voter-mandated Brexit without causing an economic crisis worth billions of dollars.

Britain’s opposition Labour party is also politically divided on the issue. Its Brexit spokesman has joined some Conservative opponents in calling for a second referendum as a potential voter-endorsed escape route for the entire project, but the party's leader is unconvinced.

Theresa May is "determined" to seal a deal. Ben Stansall / AFP - Getty Images

May’s prospects were weakened this week when Northern Ireland’s Democratic Unionist Party, which was propping up her minority government in the House of Commons, withdrew its support.

And Spain threw another wrench into the works on Thursday by suggesting it would veto May’s deal unless it was given bilateral rights over the future of Gibraltar, a British territory that Madrid has been trying to reclaim for centuries.

Austria's minister for Europe, Gernot Bluemel, issued a melancholy summary. “A painful week in European politics is starting," he said. "We have the divorce papers on the table; 45 years of difficult marriage are coming to an end."