The consultative referendum held on June 23, 2013, showed that a majority of British voters are in favour of leaving the EU. Markets reacted and adapted, and politics made the first steps towards a UK outside the EU and an EU without Britain. This paper looks at the expected effects of Brexit in different fields: political and social effects, consequences for production and trade, and financial and fiscal effects. It then presents the institutional process of leaving the EU, stressing its indeterminacy, and considers the first steps undertaken so far. It concludes that the EU negotiation position is weak because of its internal problems and calls for the priority given in reforming the EU.