The post-Brexit trade talks may be inching towards an agreement - but it is still possible the two sides will run out of time.

The current transition period, during which the UK continues to follow EU rules, began when the UK left the EU, on 31 January, and it ends on New Year's Eve.

If there is no agreement by then, the UK would have no deal with the EU on trade, or on other issues such as security co-operation and fishing.

But could there be a legal fix to allow both sides to keep talking if necessary?

And what would happen if a deal was agreed only at the very last minute?

Could the transition period be extended?

The transition period was designed to preserve current arrangements temporarily and avoid disruption, to allow for negotiations.

But there is no legal basis for extending it.

It's part of an international treaty, the Brexit withdrawal agreement, that said any extension would have to be agreed before 1 July 2020.

And the UK decided not to ask for an extension.

Could there be another sort of extension?

If they wanted to, EU governments and the UK could, in theory, come up with an international agreement outside EU law to give them a temporary extension.

Some international lawyers have also suggested it might be possible to reuse Article 50, the legal basis for the UK's exit from the EU.

But EU lawyers have rejected that.

Any plan for a further brief extension would probably be challenged in the courts.

But it could buy a few extra weeks before that challenge was heard.

Again in theory, that could allow the two sides to complete negotiations not quite finished or give more time for parliaments on both sides to examine a deal properly.

The UK has said in the past it will not consider any kind of extension.

But it wouldn't be the first time the impossible suddenly becomes possible in negotiations involving the EU, once creative lawyers sit down at the table.

"It's legally tricky," Catherine Barnard, professor of EU law, at the University of Cambridge, says.

"But you should never underestimate the ingenuity of lawyers, particularly when their backs are up against the wall."

Is a last-minute deal possible?

Any agreement would need to be vetted by lawyers on both sides - they call it "legal scrubbing" - and translated.

Most of that has probably already been done - there are only a few areas of disagreement left.

• What are the sticking points in Brexit trade talks?

But the deal would still have to be scrutinised and approved - or ratified - by parliamentarians.

And the time to go through hundreds of pages of dense legal text with any degree of thoroughness is fast running out.

The information for this blog post was taken directly from the BBC's website, to see the source and full article please click here.