Britain has voted to leave the European Union. And inevitably, this decision now leads to the question of how that will be achieved.
Politicians who are discussing the referendum result will cite Article 50 of the 2007 Lisbon Treaty - the mechanism by which a member state can leave the union.
And here's everything you need to know about the process.
What is Article 50?
Article 50 of the Lisbon Treaty is the official method by which Britain and any other member state can start the process of leaving the EU.
The article states that any member state of the EU can leave the bloc "in accordance with its own constitutional requirements".
That means we can leave the EU according to our own laws.
What happens when Article 50 is triggered?
When the UK does trigger Article 50, it must formally notify the EU of its intention and begin a period of negotiation over the UK's future relationship with the union lasting up to two years.
The article states: "The Union shall negotiate and conclude an agreement with that state, setting out the arrangements for its withdrawal, taking account of the framework for its future relationship with the union.
"It shall be concluded on behalf of the Union by the (European) Council, acting by a qualified majority, after obtaining the consent of the European Parliament."
When will Article 50 be set in motion?
David Cameron, in announcing his resignation as Prime Minister, said he would leave it to his successor to invoke the law, meaning it will not happen until after a new leader is in place in the autumn.
The two-year period starts when a member state informs the European Council of its intention to leave but can be extended by a unanimous vote of the Council members.
If a deal can be reached within two years, EU treaties will cease to apply from the date that agreement enters into force.
But if no deal on withdrawal is achieved - and any of the other 27 states block an extension of talks - membership ends automatically after the two-year period, leaving the departed state to operate under international rules set by bodies such as the World Trade Organisation (WTO).
What are people saying?
Labour leader Jeremy Corbyn said the process should begin immediately but others, including Leave campaigners Liam Fox and Andrea Leadsom, have said it is right to hold off.
Fox has called for a "period of calm" and reflection before starting the process.
Meanwhile, Remain campaigners argued during the campaign that shortly after invoking Article 50, the UK would find itself considering Article 49 - which sets out the conditions for rejoining. Although, it is unlikely this will happen once the process begins.
The article states: "If a State which has withdrawn from the Union asks to rejoin, its request shall be subject to the procedure referred to in Article 49."