Which process Britain should follows to exit from European Union(EU).? Full details about Lisbon Treaty

Any Member State may decide to withdraw from the Union in accordance with its own constitutional requirements. It should follows the Procedure mentioned in the Article 50 known as "Lisbon Treaty".

The Lisbon Treaty became law in December 2009, eight years after European leaders launched a process to make the EU "more democratic, more transparent and more efficient".

It's an agreement signed by the heads of state and government of countries that are part of the EU.

Aricle 50

Under the Lisbon treaty, a member state wishing to leave the EU should first notify the European Council its decision, triggering Article 50. This would set in motion a process by which the member and the EU leadership will negotiate the terms of the departure and reach and agreement in two years. This means even if the British government invokes the Article 50 now, the earliest exit of Britain will take place after two years.

 Constitutionally, the decision to invoke the article is the Prime Minister’s alone.

Even if the new British Prime Minister triggers the Article 50, Britain need not necessarily leave the EU after two years. If there’s no agreement by the end of the two-year period, the EU could unanimously extend the talks.

Once Article 50 is activated the UK is cut out of EU decision-making at the highest level and there will be no way back unless by unanimous consent from all other member states.

Article 50- Lisbon Treaty:

1. Any Member State may decide to withdraw from the Union in accordance with its own constitutional requirements.

2. A Member State which decides to withdraw shall notify the European Council of its intention. In the light of the guidelines provided by the European Council, 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. That agreement shall be negotiated in accordance with Article 218(3) of the Treaty on the Functioning of the European Union. It shall be concluded on behalf of the Union by the Council, acting by a qualified majority, after obtaining the consent of the European Parliament.

3. The Treaties shall cease to apply to the State in question from the date of entry into force of the withdrawal agreement or, failing that, two years after the notification referred to in paragraph 2, unless the European Council, in agreement with the Member State concerned, unanimously decides to extend this period.

4. For the purposes of paragraphs 2 and 3, the member of the European Council or of the Council representing the withdrawing Member State shall not participate in the discussions of the European Council or Council or in decisions concerning it.