Accountancy firm PwC has warned companies here to prepare for the worst from Brexit, adding that it is likely that no trade agreement will be in place between Britain and the EU by March 2019.
This could result in the imposition of tariffs in many areas, in line with World Trade Organisation rules.
The PwC report predicts that the UK will become a "Third Country" for trade purposes by the end of March 2019, when it will no longer be a member of the EU or a member of the European Economic Area.
PwC believes that the UK will not concede on free movement of people and it will not continue to make ongoing financial contributions to the EU.
It also believes that Brussels will prioritise negotiations on the UK's divorce terms and will insist that the UK make a settlement on outstanding liabilities. This is estimated to range from €24.5 billion to €72.8 billion.
Once sufficient progress has been made, it appears that only then will the EU commence negotiations on the future trading relationship, PwC adds.
PwC also stated that there is simply not enough time for a trade deal to be reached, with the UK government admitting that a full suite of trade deals could take up to 10 years to negotiate.
Feargal O'Rourke, Managing Partner at PwC Ireland said that operating WTO rules - which now looks like the most probable path - may involve some lengthy negotiations between the UK and the WTO, the outcome which would most likely impact Ireland.
"In its most simplistic outcome under WTO, Ireland would trade with the UK under the current list of tariffs and quotas operated by the WTO as applied to trade between EU Member States and Third Countries. However, as special deals may be sought by the UK from the WTO, for certain sectors for example, there may be a period of uncertainty as any such negotiations take place," Mr O'Rourke added.
However, PwC said it expects the Common Travel Area between Britain and Ireland to be retained, but added that companies need to consider the impact of Brexit on their mobile workforce.
It also said that businesses now have time to make the necessary preparations for the UK's formal withdrawal.