The British government has published the full advice

The proposed temporary backstop for the Irish border could last indefinitely.

That's according to the British government's legal advice on Teresa May's Brexit plan.

The legal advice has now been published in full, after the government was forced to do so after being found to be in contempt of parliament.

The co-leader of The Green Party in the UK, Caroline Lucas, has published excerpts from the text.

The Shadow Brexit Secretary Kier Starmer has tweeted to say the development reveals "central weaknesses in the government's deal".

He also says it's 'unthinkable the government tried to keep this information from parliament'.

Sky's political editor Faisal Islam explains.

"Northern Ireland would stay in the Customs Union, the EU's Customs Union, the rest of GB would be in a new, separate bare bones customs union.

"Which means - and it says this - there would be the need for some customs declarations between GB and Northern Ireland".