Chief financial officers (CFOs) from some of the world's largest firms are unsure whether the U.K. will be thrust into the unknown post-Brexit, according to a new survey conducted by CNBC. The results of the survey come at a time when U.K. Prime Minister Theresa May is fighting for her political survival, after the government's draft divorce deal with the EU prompted a flurry of cabinet ministers to resign. May is currently trying to rally enough lawmakers to back the proposed plan in order to get it through Parliament next month - a daunting task given the broad criticism it has received. Global CFOs across a wide range of industries were asked whether they expected Parliament to approve a formal Brexit deal with the EU over the coming weeks.

An Anti-Brexit campaigner Steve Bray (R) stands with placards and a pro-Brexit supporter (L) stands with a placard demanding an immediate departure from the European Union. DANIEL LEAL-OLIVAS | AFP | Getty Images

Just over 51 percent of respondents said they expected a withdrawal arrangement to be approved by British lawmakers in early December. Almost a third of global CFOs said they did not know what would happen, while 16.2 percent predicted a no-deal scenario. The most divided participants in the survey were EMEA-based, with the majority of CFO's in the region saying they expected a formal deal. However, almost a quarter said they feared both sides would be unable to agree on the terms of Britain's exit from the bloc. A no-deal scenario is generally considered to be where the U.K. crashes out of the EU without any formal relationship and must then rely on WTO trading rules. Responses to the CNBC Global CFO Survey are anonymous. All 37 CFOs who completed the survey responded to this question.

What's going on with Brexit?

The British government unveiled its long-awaited draft withdrawal agreement last week, which details the terms of the U.K.'s departure from the EU on March 29, 2019. May is facing opposition from across the political spectrum to the proposed draft deal, which must be approved by Parliament, with critics saying it could leave Britain indefinitely tied to the EU post-Brexit. Despite some mutinous members of the prime minister's own party looking to force through an imminent leadership challenge, prominent Brexiteers in the cabinet have also rallied behind May. Market participants are now turning their attention to an EU summit on Sunday. If the 27 remaining member states agree to sign off on the draft agreement later this week, the British government will have to win over lawmakers at a crucial vote in early December.

Impact of no-deal