The Irish backstop is part of the government’s withdrawal agreement with the EU, and is effectively an insurance policy designed to avoid a hard border between Northern Ireland and the Republic of Ireland. We’ve explained how it works in more detail here.
There are, broadly, three forms of Brexit which don’t lead to the backstop. The first is if the withdrawal deal gets passed by Parliament, and the UK and EU agree a deal on their future relationship by the end of the transition period (in December 2020). The UK could ask to extend the transition period by one or two years, but after that the backstop automatically kicks in if no future trade deal has been struck.
The UK and the EU have committed in the withdrawal agreement to use their “best endeavours” to find a trade deal which avoids the need for the backstop—that would be a new arrangement that avoids a hard border in Ireland.
The second form of Brexit that doesn’t involve the backstop is if we leave the EU with no deal on 29 March 2019. A no deal Brexit would mean that the withdrawal agreement (which contains the provisions for the backstop) has been rejected by the UK parliament and no alternative withdrawal agreement has been agreed either.
The third scenario is that parliament rejects the withdrawal agreement and the UK arrives at another arrangement with the EU. One possible way this plays out is that parliament asks the Prime Minister to go back and renegotiate her deal with the EU. It is very unlikely that a re-negotiated agreement would not include a backstop though. In September, the President of the European Council said: “there will be no Withdrawal Agreement without a solid, operational and legally binding Irish backstop.”
If we fall into the backstop arrangements, they apply indefinitely until "alternative arrangements" which avoid a hard border on the island of Ireland are agreed to replace it. We also can’t legally leave the backstop unless the EU agrees.
This article is part of our Ask Full Fact series on Brexit, answering your questions about Brexit and the latest negotiations between the UK and the EU.
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