Why is Brexit so complicated?

The UK has been integrated into Europe for over 40 years. Leaving it is complicated and messy. Here are some of the fundamental reasons why:

The UK has been a member of the EU (or previous bodies such as in the European Communities) for over 40 years. That means it's a difficult relationship to untangle. There's laws to figure out, divorce money to settle and the UK is part of 100s of schemes and different EU related agencies which cover anything from defence to regulation of chemicals.       The EU receives roughly 44% of all of our exports and roughly 53% of all our imports come from the EU. Now many people want to protect that trading relationship with the EU while other people believe that EU economies are stagnating and the UK would be better off trading with bigger countries around the world.       N Ireland poses a difficulty. After much violence in a period of time called the Troubles on the border between the Republic of Ireland and N Ireland, a peace treaty was signed which alludes to the fact that security would be breached if there was a hard border.        MPs have different points of view on what Brexit should look like. This could be based on ideological reasons, economic reasons or what would impact their constituency the most. Some MPs believe that the UK needs to be an independent trading nation, some believe that immigration is necessary for their local industry and others may believe that having EU laws and regulation is a good/bad thing.
The UK has been a member of the EU (or previous bodies such as in the European Communities) for over 40 years. That means it's a difficult relationship to untangle. There's laws to figure out, divorce money to settle and the UK is part of 100s of schemes and different EU related agencies which cover anything from defence to regulation of chemicals. The EU receives roughly 44% of all of our exports and roughly 53% of all our imports come from the EU. Now many people want to protect that trading relationship with the EU while other people believe that EU economies are stagnating and the UK would be better off trading with bigger countries around the world. N Ireland poses a difficulty. After much violence in a period of time called the Troubles on the border between the Republic of Ireland and N Ireland, a peace treaty was signed which alludes to the fact that security would be breached if there was a hard border. MPs have different points of view on what Brexit should look like. This could be based on ideological reasons, economic reasons or what would impact their constituency the most. Some MPs believe that the UK needs to be an independent trading nation, some believe that immigration is necessary for their local industry and others may believe that having EU laws and regulation is a good/bad thing.