UKIP and Brexit: what does the manifesto say?

Now that the EU referendum has been set for June 23rd, we will be bringing you new factchecks and explainers on topics ranging from immigration to trade. We will also be going over all of our older content on Europe and the EU to make sure it's ready for voters.

Some posts will be rewritten, others will be kept up for historic interest or archived. This is one of the posts we'll be reviewing.

Last week UKIP set out its plan for exit from the European Union, outlining two options:

• "We repeal the European Communities Act 1972 and leave immediately.
• We activate Article 50 of the Lisbon Treaty and notify the European Council that the UK has decided to leave the EU in two years' time."

The basis of UKIP's first option is that Parliament is supreme. In the opinion of the courts and many legal experts, and as stated in a law passed in 2011, the UK decides whether or not to accept EU law. UKIP say that, as a result, we could "leave immediately" if Parliament were to repeal the piece of UK legislation that gives EU law its power in this country: the European Communities Act 1972.

In practice, this course of action would give no time for the UK to renegotiate its relationship with the EU—politically, and in terms of trade—and doing so could be more difficult once the UK is out.

Such a prospect isn't UKIP's first choice either. It prefers the second option: to withdraw in accordance with EU law. That law says that every member state has the right to withdraw from the Union (the idea that the EU can stop a country leaving is a myth). But its departure must take place in a particular way.

The process is set out in Article 50 of the Treaty on European Union. It says that the UK—or any other member state that wants to leave—can notify the European Council of its intention to withdraw once the decision has been made internally. In practice, that would happen by referendum in the UK.

Once it notifies the Council, Article 50 envisages that the EU and the UK will enter into negotiations in order to arrive at a "withdrawal agreement".

"Having activated Article 50 of the Lisbon Treaty, we will set a fixed date, two years ahead, on which we intend to leave, while recognising we could leave earlier. Then we will begin amicable negotiations"

Article 50 says the longest that a member state will remain in the EU after it gives notice that it wants to leave is two years (unless there is unanimous agreement between that state and the Council to extend the cut-off point).

But if a withdrawal agreement is reached within those two years, and specifies a different departure date, that could happen in theory.

Activating the procedure and trying to leave before two years without a withdrawal agreement would be likely to contradict Article 50 and trigger an argument with the EU.

It's worth bearing in mind that no country has actually left the Union using Article 50, so how the departure procedure would be implemented in practice is hard to predict.