British Prime Minister Theresa May is expected to outline her plan for a 'hard Brexit' that includes regaining full control of UK borders and taking Britain out of the single market.
In the speech tomorrow in front of diplomats at London's Lancaster House, Mrs May will outline the priorities for the UK once Article 50 is triggered.
This includes withdrawing from the single market and the European customs union - to regain control of immigration and end the jurisdiction of the European Court of Justice.
But the speech, which was partly leaked to the UK media, is likely to spark a backlash from business figures concerned about higher tariff barriers and the impact on the Northern Ireland Border.
A spokesman for the Irish Government said it didn't want to pre-empt the speech but said there needed to be "clarity from the UK as soon as possible".
"We are aware of speculation regarding content of the speech the prime minister is expected to make on Tuesday. It's not appropriate to comment on speculation and we look forward to hearing what the prime minister has to say," he told the Irish Independent.
"It's clear that there is need for clarity from the UK as soon as possible on the proposed approach for negotiations.
"Ireland's key priorities remain: economy and trade, common travel area, Northern Ireland (peace process) and the future of Europe."
Conservative MP Nicky Morgan, the pro-Remain former UK education secretary, said Mrs May should be seeking "maximum participation" and warned her not to damage the economy for the sake of controlling immigration.
Labour leader Jeremy Corbyn accused the PM of pursuing "an extremely risky strategy", taking the UK in "the direction of a bargain basement economy".
"It seems to me a recipe for some kind of trade war with Europe in the future. That doesn't really seem to me a very sensible way forward," he said.
Meanwhile, British Chancellor Philip Hammond has fired a warning shot across the bows of Brussels over the issue of the single market.
In an interview with a German newspaper, Mr Hammond said the government would do "whatever we have to" to ensure UK businesses remained competitive if European markets were "closed off" to them.
The chancellor told 'Welt am Sonntag' that the UK "could suffer from economic damage at least in the short-term" if it were left with no access to the EU after Brexit. He suggested Britain could cut taxes to encourage companies to move to the UK in retaliation.
Asked if the UK's future was as the corporate "tax haven of Europe", the chancellor said ministers were ready to change if they had to.
"If we have no access to the European market, if we are closed off, if Britain were to leave the European Union without an agreement on market access, then we could suffer from economic damage at least in the short-term," he said.
"In this case, we could be forced to change our economic model and we will have to change our model to regain competitiveness. You can be sure we will do whatever we have to do.
"The British people are not going to lie down and say, 'too bad, we've been wounded'. We will change our model, and we will come back, and we will be competitively engaged."
Mr Hammond also said there was a possibility of "a time period between Britain leaving the EU and the full introduction of a long-term future arrangement between the UK and the EU" to allow companies to prepare for the new regulatory regime.
Lord Lawson of Blaby, who was Conservative chancellor in Margaret Thatcher's government in the 1980s, warned that the EU would reject any offer of a free trade deal.
"We must accept that our free trade offer will be rejected and that no remotely acceptable post-Brexit trade agreement between the UK and the EU is negotiable," he said, writing in a Policy Exchange pamphlet.
He said it was "incontrovertible" that "in common with the rest of the world, we should be outside both the so-called single market and the customs union".
"This is not a 'hard Brexit': it is Brexit," he said.
This week various obituaries to TK Whitaker were constant in their praise of Mr Whitaker's ability to break with conventional wisdom. It is ironic that many of these obituaries came from people deep inside the Irish establishment who have never questioned Ireland's conventional wisdom in their lives.