Why are we now talking about border checks?
It has emerged that the UK put forward controversial proposals to set up a string of customs posts on either side of border which would replace the Brexit backstop.
The reported plan was contained in the British government’s so-called ‘non-papers’ and would set up customs clearance sites between 5-10 miles from the border on both sides.
Both the EU and Ireland have repeatedly stated that they will not tolerate a return to a hard border.
What does Boris Johnson say?
The British Prime Minister reacted by saying the reports refer to previous ideas and his Government is going to be tabling other measures.
However, he has continued to reject the Withdrawal Agreement and said his Government would be making a "very good offer" when it tables proposals soon.
Why is there such a problem with the Withdrawal Agreement?
The 599-page withdrawal agreement was agreed between the EU and UK negotiators in November 2018.
It sets out how the UK leaves the European Union and covers citizens' rights, border arrangements, money and also a transition period.
The deal was endorsed by all of the other 27 EU member states before then prime minister Theresa May went back to the UK parliament in a bid to get the agreement passed.
Despite a number of clarifications from the EU, Mrs May was unable to get backing for the deal in the House of Commons which has so far rejected it three times.
One of the main points of contention is the Northern Ireland backstop.
What is the problem with the backstop?
The backstop is essentially a clause included in the main Brexit withdrawal agreement which aims to protect the Good Friday Agreement and the peace process.
It ensures that if a long-term trade deal has been agreed by the end of 2020 that avoids a hard border between Northern Ireland and the Republic of Ireland, and if there is no extension to the transition period, then a backstop consisting of "a single customs territory between the EU and the UK" will be triggered.
This backstop would only be implemented if a solution cannot be negotiated after the transition period and would not be introduced during the initial transition phase as the UK will continue to participate in the EU customs union and the single market.
The DUP is staunchly against the backstop as it leaves open the possibility of divergence between Northern Ireland and the rest of the UK.
Mr Johnson has also stated that his Government cannot accept the backstop, even if this means leaving the EU without a deal.
The British Government is adamant that the UK will leave the EU at the end of this month - with or without a deal. Time for a deal is running out.
A number of political leaders, including the Taoiseach, have said that if an agreement is to be signed-off on at the next EU Council meeting on October 17, the UK would have to put forward workable alternative solutions this week.
Today, Mr Johnson said he would be presenting "very good" proposals in the coming days and urged the EU to work with him to break the Brexit deadlock.