The vote is over - now how does Britain actually leave the EU?

The mechanics of leaving the EU.

The people have spoken. Brexit is go. But what does the process involve?

The answer lies in Article 50 of the Treaty on European Union. Invoking it is the means by which a member state notifies the EU of its intention to leave. That sets a two-year clock ticking, during which the EU is obliged to negotiate a withdrawal agreement with the departing state, setting out the arrangements for withdrawal and taking into account the framework for its future relationship with the EU.

The various EU treaties by which member states are bound will cease to apply to the departing country from the date of the withdrawal agreement coming into force or, failing that, two years after giving notification of withdrawal – unless the European Council and the departing state agree to extend the negotiating period. During that two-year negotiaton period, EU laws will still apply to the UK and the UK will continue to participate in other EU business as normal, but it cannot take part in any internal EU discussions regarding its departure. The UK will not be able to vote on its own withdrawal agreement but each of the remaining EU states has a veto over the terms of Britain’s withdrawal, which means any one of the 27 could prove to be an obstacle.

On the EU side, the negotiating is done by the European Commission. The terms for a withdrawal are far from cut and dried – after all, no other country has ever decided to leave the EU – so there is no guarantee that the UK would accept them. Certain parts of the agreement may have to be ratified by every national parliament in the EU.

The EU treaties will also need to be amended to reflect the UK’s exit, which would require unanimous agreement from the remaining 27 members states.

In theory, there is nothing to stop Britain from leaving the EU unilaterally – that is, without consent – simply by the UK government repealing the 1972 European Communities Act. But doing it this way would damage the chances of future trade deals between Britain and the EU. It would also mean no transition period. EU laws which directly affect the UK would cease to be valid with immediate effect and the UK would need to pass new ones swiftly.

When Article 50 is triggered is up to Britain but the EU leadership has already said it should be “as soon as possible.”

After negotiating the withdrawal comes the even harder task of bashing out new agreements on trade and other issues, which could take another five years.

Mr Cameron will face his European counterparts at a European Council summit next week. The foreign ministers of the six founding nations of EU – France, Germany, Italy, the Netherlands, Belgium and Luxembourg – are meeting on Saturday. The talking – and the exclusion – has begun.