What is there to say at this point? The Brexit talks are stalled with little prospect of change on either side. The issue at hand is the backstop. None of the possible permutations for how to resolve the question can satisfy all of the following: the Irish government, the Conservative Party, the DUP and the Westminster Parliament.

The backstop is, in essence, an insurance policy for Ireland: that come what may, even should trade talks between the United Kingdom and the European Union collapse or stall for a long period (as trade talks are prone to do due to changes of government or other shifts in the political weather on both sides) there will be no change to arrangements on the border between Ireland and Northern Ireland. While the Withdrawal Agreement is settled by qualified majority voting, the final trade agreement between the EU and the UK is subject to a veto from all member states, including Ireland. So any backstop arrangement has to provide that assurance to the Irish government, which is why a backstop with an in-built time limit is nothing doing.

For the DUP, however, any arrangement which creates greater barriers between Northern Ireland and the United Kingdom than exist between Northern Ireland and Ireland is an existential threat to their central political project. So the backstop must cover the whole of the United Kingdom if is to pass without bringing the confidence and supply arrangement between the DUP and the Conservatives to an abrupt end. So any backstop has to cover both Northern Ireland and the United Kingdom to satisfy the DUP.

But some Conservative MPs - including several in the Cabinet - fear that a backstop without a time limit would last forever. So the only backstop that can pass through the Conservative Party is a time-limited one...which is unacceptable to the Irish government, and so the deadlock continues.

What could break the deadlock? There's a crucial difference between the three groups that two of the players - the DUP and the Irish government - have a mandate to suffer economic damage and the Conservative Party very much doesn't. In theory, in a negotiation where one party has more to lose than the others, that party blinks. The problem is that there are enough people within the Conservative Party who think that they can survive a head-on collision. It may take going over the cliff to convince the that they can't survive the fall.