Brexit refers to the UK's planned withdrawal from the EU following a 2016 referendum where 52% voted to leave. The UK has divided opinions on Brexit, with the 'leave' camp arguing against EU immigration policies and the 'remain' camp concerned about potential economic repercussions. The process of leaving involves invoking Article 50 of the EU treaty, which requires negotiations among all member states and approval of terms, potentially leading to a protracted exit process.