The Brexit draft withdrawal agreement between the U.K. and the EU which was finally reached last week is great news for Ireland. But only if it sticks and is implemented -- and there is little confidence in that happening.

It barely got through a marathon meeting of the British Cabinet last week, with several ministers resigning. It still has to get through a vote in the House of Commons where the numbers are stacked against it.

The most contentious part has to do with Ireland and the requirement to avoid the return of a hard border between north and south. A year ago, to move the talks with the EU forward, the British agreed to "the Irish backstop,” a guarantee that whatever happens in the Brexit negotiations the return of a hard border in Ireland is ruled out. British Prime Minister Theresa May has been grappling with the implications of that commitment ever since.

It's a real conundrum since after Brexit the north of Ireland will be outside the EU and the south will still be inside, which normally would make a hard border inevitable. Initially, the solutions proposed were centered on ideas about the North remaining aligned to much of the EU single market rules and even remaining in the customs union so that goods could continue to move freely between north and south, and there would be no need for hard infrastructure at the border.

However, this meant there would have to be an invisible border down the Irish Sea, partly to protect the U.K. but also to protect the EU from goods coming into the North from the U.K. (outside the EU) and on into the south (inside the EU). This would mean checks at ports on the British mainland and/or in the North.

Read more: Worst joke of the year pokes fun at Irish Famine, Brexit

The DUP, the unionist party propping up May's government at Westminster, said this could never happen because it meant the North would be different to the rest of the U.K., something that was completely unacceptable to them since it could be the start of the break-up of the United Kingdom of Great Britain and Northern Ireland.

Since May depends on the DUP votes for her survival, she had to come up with something else. Her solution was that the whole of the U.K. would stay in the EU customs union for the time being, and in addition, the EU's single market rules and standards would continue to apply in the North for many traded goods. So no need for a hard border in Ireland or an invisible border in the Irish Sea.

That compromise is now written into the draft withdrawal agreement. For the south of Ireland, it could not be better.

Solving the north/south border issue was important to us, but if an agreement had been limited to that it would have left our trade across the Irish Sea, which is huge by comparison, exposed. The draft withdrawal agreement proposal that all the U.K. should remain in the customs union means our trade with the U.K. would continue as usual and thousands of jobs here would be saved.

It's like Santa Claus has come early to us. However, it's easier to believe in Santa than it is to believe that this draft withdrawal agreement is going to stick.

The fact that the U.K. staying in the customs union would be for a limited but undefined length of time, and only to allow something better to be negotiated eventually, has cut no ice with the Brexiteers, both inside May's Conservative Party and outside it.

The British Labour Party is divided, partly because if the government falls on this issue they could win the subsequent election. And the DUP is still adamantly opposed because of the special provisions which would apply to the North only. Even neutral observers say that a majority across the House of Commons will vote against the draft withdrawal agreement.

Those opposing the agreement say it is the worst of all worlds. It means the U.K. would be outside the EU in name only, despite the British people voting to leave the EU in the 2016 referendum. It means the U.K. would still have to pay into EU finances but would have no say in EU policy.

Read more: Were Unionist leaders too bigoted to realize Brexit brings a united Ireland closer?

Above all, staying in the customs union would mean the U.K. would be unable to strike its own trade deals with the rest of the world, one of the main reasons for leaving.

They also fear that remaining in the customs union until something better can be negotiated might mean staying in for years. There is a suspicion that the EU could string the U.K. along indefinitely, that there is no solution to the Irish border issue, that sentiment in Britain might change and the U.K. might never get out. Which is why those opposed describe it as a Hotel California Brexit (you can check out any time you like, but you can never leave).

May is in an impossible position as she tries to cling to the leadership. She is remarkably resilient, insisting that this is the best way forward for the U.K. and much better than crashing out at the end of next March with no deal which would be catastrophic. She admits it is a compromise but says it still honors the vote to leave the EU while protecting the economy and jobs.

By now the penny has dropped with many people in the U.K. that, however much they may dislike the EU, disentangling the U.K. economy after 40 years of membership is far more complicated than they were told before the 2016 referendum. The potential for damage, loss of jobs and a recession that could last for years is huge. The promised upside of new trade deals with countries around the world looks very uncertain and very unlikely to compensate for being shut out of the EU, the biggest single market in the world.

That realization has been there for some time among the business community in the U.K. which sees the whole thing as a gigantic mess. It was also evident in the north of Ireland last week when business and farming leaders, usually the backbone of unionism, were publicly calling on the DUP to back the draft withdrawal agreement, saying it was the best hope for the future of the North.

In the south, the Irish government has been low key in its reaction to avoid upsetting the unionists even more. There is also the realization that although the agreement gives us what we wanted, it could be very short-lived.

There is growing concern here that May will fail to get it through Parliament and we will be faced with the aftermath of a no deal Brexit with Britain crashing out next March. That would mean a hard border between north and south, imposed more by the EU than the U.K. It would also devastate our trade with the U.K., particularly in the agri-food sector, as the U.K. starts to import cheap food from around the world.

Even if it does not get that bad and there is a last minute attempt to strike a tweaked Brexit deal, it's uncertain what will happen when push comes to shove. Will the EU continue to insist there is no hard border in Ireland? Or will they tell us to find a security solution and deal with the situation?

We tend to forget that other countries in Europe are anxious to strike a deal with the U.K. on Brexit to protect their own trade, and privately they may be losing patience with a dispute over a border in an island on the far western edge of the continent. One wonders how supportive we would be if the boot was on the other foot and a similar dispute over a border between areas on the other side of Europe was holding up a deal of economic importance to us.

It's important to remember that the draft withdrawal agreement deals only with the mechanics of the U.K.'s departure from the EU after it leaves next March -- the transition parameters including the Brexit bill for the U.K., the Irish backstop and citizens' rights. During the transition period of the next two years, assuming the agreement is accepted in the U.K., nothing would change on the ground.

During that time the more important negotiations on the future relationship -- including a trade deal -- would take place. If all goes well the U.K.'s transition out of the EU would then finish at the end of 2020.

There is still the possibility that May will survive and her version of a soft Brexit will prevail, with some kind of free trade agreement with the EU that is close to a permanent customs union. There are hints of this possibility in the short political declaration document (non-binding) that was published last week as an addendum to the draft withdrawal agreement suggesting pathways forward. Over the coming weeks, business and other groups in the U.K. will be campaigning to have this vision accepted, as well as the draft withdrawal agreement which would facilitate it becoming a reality.

The alternative would drive the U.K. over the Brexit cliff edge into the unknown. The hope is that enough members of Parliament on all sides in Westminster -- even the DUP -- will get the message, realize what is in their best interest and stop playing politics. It's a slim hope but it's still there. If the Parliament votes down the agreement, there will be pressure for a people's vote (another referendum) to end the gridlock.

For Ireland, north and south, the stakes could not be higher.

Read more: Are you eligible for an Irish passport before Brexit?

British Prime Minister Theresa May announcing her Brexit deal.Sky News still