The report by the two firms assessed the impact of new tariff and non-tariff barriers that might be imposed on trade between the union and the United Kingdom post-Brexit.
"The annual direct (or "red tape") cost of WTO [World Trade Organization] tariff and non-tariff barriers is estimated to total around £27 billion for UK firms (or equivalent to 1.5 percent of GVA [Gross Value Added]) and around £31 billion for EU27 firms (or equivalent to 0.4 percent of GVA) after initial steps to mitigate the impacts have been taken," the report read.
According to the report, about 70 percent of the aggregate cost will split among five sectors in the United Kingdom: financial services, agriculture, the food industry, consumer goods, and the chemical industry.
Meanwhile, London and Brussels can reduce the cost of Brexit for their firms if the two parties negotiate a new customs agreement that would have a lot in common with the existing EU Customs Union.
"[The new agreement] would likely reduce the UK direct costs to £17 billion (equivalent to 1.0 percent of GVA) and for the EU27 to £14 billion (equivalent to 0.2 percent of GVA)," the report said.
The United Kingdom is currently part of the EU single market but if London leaves it post-Brexit, the country will have to negotiate new trade deals with its partners.
Brexit talks between London and Brussels officially started in June and are due to be completed by the end of March 2019.