Brexit: How Could 'alternative arrangements' for the Irish Border work? - BBC News
The prime minister believes "alternative arrangements" for the Irish border are the key to scrapping the controversial backstop plan and unlocking a Brexit deal.
But what are they and why are they necessary?
What's the problem?
If Brexit happens, the UK's only land border with the European Union (EU) would be between Northern Ireland and the Republic of Ireland. In theory, that would mean checks on certain products because rules and standards may not stay the same.
The worry is this could lead to a so-called hard border between Northern Ireland and the Republic of Ireland, with infrastructure installed so checks could be carried out.
To address this problem, Theresa May negotiated a solution called the Irish backstop. But it proved controversial as many Conservative MPs felt this plan would keep the UK too closely tied to the EU after Brexit with no way of getting out of it.
The political opposition to the backstop eventually led to Mrs May's resignation. Boris Johnson, the new Prime Minister, has vowed to scrap it.