By Fiachra Ó Cionnaith, Political Correspondent, in Brussels
Update 6.58pm: Irish and British businesses, banks and airlines will "bite back" and make Brexit decisions for themselves that could have dire consequences for both economies if a deal is not struck by Christmas, Taoiseach Leo Varadkar has warned.
Mr Varadkar made the claim as he admitted a realistic Brexit deal deadline date is "anyone's guess" and could be as late as January, and refused to rule out an extension to the March 29, 2019, cut-off point for Britain to formally leave the EU.
Speaking after a European Council summit undermined by fresh Brexit delay and fears a dreaded no deal scenario is now inevitable, Mr Varadkar said decisions must be made soon.
And, noting businesses work "on a quarterly basis" and cannot wait for politicians to make a last minute March breakthrough, he said if no progress is made within weeks firms may take action themselves regardless of the wider economic consequences.
"Politicians may be able to make late, late night decisions in rooms in the new year or in December but businesses are going to make plans long before that because the business sector operates on a quarter by quarter basis.
"Business, banks, employers airlines will start making decisions and they will start making decisions that bite back particularly in the United Kingdom but also in Ireland and other places.
"I think it's in the interests of all of our citizens that the politicians and officials get on with this and get it done as soon as possible," he said.
Mr Varadkar was speaking as he separately admitted a realistic Brexit agreement deadline date could be as late as January, despite repeated warnings in recent months about June, September and now October cut-off points.
Asked when he believes a deal can now be agreed just days after European Council president Donald Tusk said an agreement is "further away than ever", Mr Varadkar said the date is now "anyone's guess".
The Taoiseach said a now seemingly off the cards special November summit will only take place if there is a deal to sign off on or if "talks break down", and added that while a scheduled December EU summit could see a deal struck he could not rule out the crisis dragging on into January.
"There is another summit in December, I really hope we can have it done in November, and if we don't then we will do it in December. But to be honest I just don't know," he said.
While stressing he is "not calling for" an extension to the March 29, 2019, date for Britain to formally leave the EU amid fresh speculation over the potential move, Mr Varadkar also twice noted it is "legally possible" if London requests a delay.
The Taoiseach added that while some may view Brexit as a short-term "storm", the reality is it is the political equivalent of climate change that could ravage both Ireland and Britain if not tackled properly, warning: "It's a permanent change."
Update 5.48pm: The Taoiseach Leo Varadkar has warned businesses will "bite back" if politicians cannot agree to a Brexit deal by Christmas.
Mr Varadkar was speaking after EU leaders failed to make substantive progress in negotiations with the UK at a summit this week.
It does look likely however that Britain will get an extra year after leaving the EU to negotiate a trade deal.
The Taoiseach said first a withdrawal agreement has to be put together, and it will need to happen soon because businesses will make decisions long before politicians.
He said: "Businesses are going to make plans long before that.
"The Business sector operates on a quarter by quarter basis. Businesses, banks, employers and airlines will start making decisions that bite."