Theresa May was defending her Brexit plans on the BBC this morning. But she made a misleading claim in the process.

FactCheck takes a look.

The background

The Withdrawal Agreement sets out the terms on which we actually leave and arrangements for the “transition period”. It’s this agreement that Mrs May has been trying to negotiate for the last two years, and she’s now putting it through Parliament.

The transition period kicks in on the day we leave the EU – currently scheduled for 29 March 2019 – and lasts until the end of 2020.

During the transition period, we’ll be negotiating a second deal with the EU on our long-term “future relationship”. If we can’t strike that second deal before the end of the transition period, we either extend the transition, or deploy the “backstop arrangements”.

The backstop is the plan B that prevents a hard border between Northern Ireland and the Republic of Ireland. But as the government’s now-infamous legal advice shows, if we get into the backstop, we can’t leave without the EU’s permission.

What did Theresa May say?

It’s this backstop point that’s really caused problems for Mrs May this week. She appeared keen to downplay the chances of it ever being needed – it’s supposed to be a last resort.

Describing what would happen if we don’t reach a future relationship deal by the end of the transition period, she said:

“The question is: do we go into the backstop? Do we extend, what I call the implementation period, what’s become known as a transition period? A decision has to be taken at that point in time. And what we negotiated is that actually it’s for the UK to choose which of those we want to go into.”

You might hear those words and think that we have complete autonomy over whether we enter the backstop or extend the transition.

But that’s not true.

Let’s take a look at the text of Mrs May’s Withdrawal Agreement.

Article 3 says the UK “may at any time before 1 July 2020 request the extension of the transition period referred to in Article 126 of the Withdrawal Agreement”.

But Article 132 says “the Joint Committee may, before 1 July 2020, adopt a single decision extending the transition period for up to one or two years.” The Joint Committee is made up of the UK and the EU.

That means the UK can ask for an extension to the transition, but only the UK-EU Joint Committee is able to actually make the decision to extend.

On that basis, we think the PM’s comment this morning that “it’s for the UK to choose which of those [backstop or extended transition period] we want to go into” is misleading.

We may be able to choose whether or not we ask for an extension, but we still need EU agreement – via the Joint Committee – before it can be granted.

This could mean the UK is forced into the backstop arrangement if the EU doesn’t agree to extend the transition period. And once we’re in the backstop, we can’t leave that without permission from Brussels either.

We put this to Number 10. A spokesperson told us “the Withdrawal Agreement is clear that in the unlikely event that we don’t get a future relationship deal before the end of the transition period, the UK can make a sovereign choice on whether to pursue an extension. If we choose the extension, then that would be agreed by the Joint Committee”.

FactCheck verdict

Theresa May said “it’s for the UK to choose” whether “we want to go into” an extended transition period or the backstop arrangements if we don’t strike a deal with the EU on our future relationship by the end of 2020.

We think Mrs May’s claim is misleading. Her words suggest the UK will have complete autonomy over whether we enter the backstop or extend the transition. But that’s not the case.

Her own Withdrawal Agreement – which she’s battling to get through the Commons right now – says that the UK can ask to extend the transition period, but only the Joint Council of the UK and the EU can grant that extension. In other words, we’ll need permission from Brussels.