Euronews understands that the gap between the EU and UK on fisheries, competition and oversight is still big enough to collapse the talks.
Just five per cent of the agreement between the EU and the UK remains open, but the sides are so far apart that talks can still fail.
Around 95 per cent of the legal text is agreed across all areas of the EU–UK future relationship, sources have told Euronews.
However the difference of position on the outstanding five per cent – relating to fisheries, governance and the so-called level playing field – are significant enough to collapse the talks.
Several sources close to the negotiations say a political intervention is needed to solve the remaining issues.
On fisheries there has been "almost no progress at all", one senior source has told Euronews.
The UK is insisting that fish stocks are distributed using the principle of "zonal attachment", or "where the fish live", which would see British trawlers access around 90 per cent of fish in UK waters.
The EU argues that this isn’t scientific as many fish stocks such as mackerel spawn off the coast of Ireland and other EU member states, so it isn’t fair to say the UK should take all of the stock.
The UK is also insisting that fish stocks are renegotiated every year. The EU is resisting this; and says it needs certainty for its fishermen.
On the level playing field – which ensures fair competition in the single market – the EU is insisting it can impose autonomous safeguard measures if the UK breaches the agreement and "endangers the level playing field".
However, the UK doesn’t want the EU having autonomous rights here.
Meanwhile, member states are calling on the European Commission to publish the EU’s contingency planning in the case of no deal.
Up until now, the commission has been hesitant to do so because measures under contingency could look more favourable to some on the UK side and might push for a no deal.
It also sends out a pessimistic tone around the talks.
There are fewer than six weeks left to go until the December 31 deadline when the transition period ends and the UK is officially out of the EU’s single market and customs union.
While it is not possible to extend the transition period, sources say a "bridging" period up until the end of January may be possible to allow for finalising the deal and ratification.
However, as long as there is no movement on key issues like fisheries, "this could all end without an agreement" said one source close to the talks.