In June 2016, UK citizens voted for a referendum that would make the United Kingdom leave the EU. This referendum had an issue with it. It never said how the UK would leave the EU or what it’s relationship would be with the EU after it leaves. Over the past 2 years, the government has been arguing about that.
On December 2018, Theresa May’s government proposed a deal on leaving the EU. Parliament was expected to vote on it on December 11th, but it was postponed to January 15th because the deal came under attack by the House of Commons.
May’s deal is very controversial. Under the deal, the UK would begin a transitional period on March 29, 2019. The transitional period would last until 2020. After that, the UK would be out of the EU. The UK would be a “single customs territory” after they leave. This would mean that the UK would leave the EU, but they wouldn’t be completely independent from the EU in areas such as trade and citizenship. Brexiteers want a completely independent UK and the deal is not what they were hoping for. The deal also says that there would not be a stricter Uk-Ireland border due to fears of violence.
If May’s deal isn’t passed by parliament this Tuesday (which is what's expected to happen), a few things could happen. One scenario is that the UK will leave the EU with the UK being completely independent. This would not be good for the country because it would do harm to the economy. Another scenario is that Theresa May will come up with another deal that is less controversial. There is also a possibility that May’s government will collapse. Finally, the UK could also decide to make a second referendum and not leave the EU after all.