Pro Brexit anti European Union Leave protesters demonstrating in Westminster on what, prior to another Brexit Day extension, would have been the day the UK was scheduled to leave the EU, and instead political parties commence campaigning for a General Election on 31st October 2019 in London, England, United Kingdom. Mike Kemp | In Pictures | Getty Images

Will the upcoming U.K. election put an end to more than three years of Brexit uncertainty? Maybe not, experts say. Prime Minister Boris Johnson's deal was approved, in principle, by British lawmakers last month but political wrangling in Westminster led to the U.K. leader pausing his Brexit bill and opposition parties agreeing to an election. Johnson said "the way to get Brexit done" was to have the national vote in December, but political analysts argue that he might be wrong. Quentin Peel, an associate fellow at the think tank Chatham House told CNBC Friday that there is a "pretty good chance we won't" have clarity on Brexit after the election. Victoria Hewson, head of regulatory affairs at another think tank called The Institute of Economic Affairs, said this is "the most unpredictable election ever."

UK 'profoundly divided'

U.K. voters are still profoundly divided over EU membership, with the 2016 referendum itself producing a 51.89% result for leave and 48.11% for remain. This division is now mirrored in the country's political system. The U.K. has traditionally been dominated by two main parties: the pro-business Conservative Party and the pro-social justice Labour party. However, both of them have failed to come up with a united position on Brexit. As a result, some of their party members have defected into other political groups or been expelled altogether. Robert Colvile, director of the Centre for Policy Studies, told CNBC that there are now five parties "that matter." Apart from the traditional two, Colvile was referring to: The Liberal Democrats — which is openly campaigning to stop Brexit altogether; the Brexit Party — whose leader, Nigel Farage, supports a no-deal breakup from the EU; and the Scottish National Party (SNP) — a pro-EU party based in Scotland. "The Brexit vote will be split," Peel from Chatham House said. His theory is based on the fact that the Brexit Party supports what it calls a "clean" breakup from the EU and the Conservative Party is arguing that the country should leave the EU but with the deal that Johnson negotiated.

At the same time, "Labour's position is extremely obscure," Hewson from The Institute of Economic Affairs said. The party has said that it will look to negotiate another exit agreement with the EU and put it to a new referendum. Under this scenario, Brexit would likely take a lot longer to happen. "It comes down to a numbers game," Hewson said. In the event of a hung parliament then Colvile from the Centre for Policy Studies argued that a second referendum on the country's EU membership is the most likely option. "If an election doesn't work (to solve the Brexit impasse), a second referendum is the last possibility," he said.

The polls have been wrong before