The British decision to leave the EU has been a long time in the making, but it does not lessen the shock that many politicians in the UK and across the EU are feeling.
Legally speaking, though, the process of actually leaving will take a lot longer. Britain will now enter a kind of phoney Brexit period. It is still a member of the EU. The referendum vote is not as such legally binding. It is advisory only – but if it is out it creates a political imperative for the UK government to arrange its exit of the EU.