Automotive industry, agriculture, financial services. Certain sectors of the European Union (EU) are particularly vulnerable to divorce without the consent of the United Kingdom and 27 partners.
"An agreement will not be made", for example, to impede barriers to restoration of customs duties and mutual recognition of environmental or health standards.
The automotive industry is a major sector of the damage. Experts warned several cases of potential disaster in the area where about 12.2 million people work.
About 10% of the European automotive industry exports will go to the United Kingdom, said Vice President Vincent Wickard, Economist for the Future and International Information Analysis Center (CEPII).
In addition, the automotive industry of the United Kingdom and the EU are highly integrated. "Sometimes some vehicles run five or six times between the United Kingdom and the continent," explains Karsten Bjeski of ING Diba. Any damage to the supply chain, for example, can be dangerous to the carriage of goods.
Strong divorce affects the well-established German automotive industry, especially in the UK. "If our supply chain stops on the border, we will not be able to continue production in the UK," said BMW BMW BMW Stephen Frismut.
It may also affect the chemicals sector. Brzeski says: "Many German, French, Dutch, or Belgian companies have production facilities." Therefore, the chain of production is particularly vulnerable.
Transnational companies such as Shell or the Anglo-American Dutch LyondellBasell, the Anglo-Dutch petrochemical group, also face specific problems with their management.
Agriculture and fisheries are also far behind. At present, 60% of UK food needs are covered by their production, the rest are mainly imported from France, Belgium, Holland and Ireland.
If customs duties are reinstated, goods will be expensive and their entry into the UK may be delayed. "We are convinced that there are locked trucks in Kale, and as they wait, they bring milk before Dowers get there," says Bjeski.
Many goods and animals may be prohibited if they are not listed in the third countries listed in the United Kingdom. This registration can take place promptly in view of the situation for former EU members.
Fishing is a problem for France, Spain, Portugal, Denmark or the Netherlands, usually working in British territorial waters.
The aviation industry is also among the victims. Airbus, which produces its own aircraft in various EU production locations, has unleashed an alarm without the Brescia approval.
In the United Kingdom, about 15,000 people who produce their wings will be "disastrous" by the European-based group of direct workers and will make it difficult to question the country's investment.
In July, German Airbus CEO German Tom Eterns expressed concern over the abolition of the United Kingdom from the European Aviation Safety Agency (EASA). "At the end of April, thousands of our aircrafts will be invalid, which will mean a break in our production," he said.
Fear of sudden deterioration of air traffic between the United Kingdom and the continent makes it a particularly sensitive sector.
The European Commission wants companies to fly to Europe and have a valid security certificate for a limited period of time. This is a British agreement.
On the other hand, financial services are also cautious in the case of Breckney. Operators set up in the United Kingdom will lose their rights ("financial passport") to provide their services without participating in 27 countries of the block.
The commission has done much to adjust the "contract and adaptation" actions across the continent.
On Friday, the Governor of the Bank of France demanded vigilance in the compensation sector because unmarried divorce "poses a threat" to the stability of the financial system.
British companies have almost monopoly in this business, that is to keep track of exchanges between financial agents in the global markets and to ensure the correct execution of transactions between all operators.