Toyota, one of the world’s largest automakers, has called for more “clarity” for businesses over Britain’s negotiations to exit the European Union, warning that the fallout from “Brexit” could badly damage its operations in the country.

The remarks from a senior Toyota executive highlight the risks facing Britain as it navigates complex negotiations to leave the European Union. Though much of the concern regarding the issues facing the country has been focused on its crucial financial industry, it is also home to a major carmaking sector, as well as a variety of other high-tech businesses that are heavily reliant on European trade and supply chains.

Automotive manufacturing in Britain is mostly foreign-owned, with Japanese carmakers like Nissan and Honda, along with Toyota, operating large, modern plants in the country. Those facilities were built largely to serve the European market, to which Britain currently has unimpeded tariff-free access.

Toyota’s facilities in Britain are just such a case, illustrating the complex supply and trading systems used across Europe by many companies. The carmaker treats its British plants, which build the Auris and Avensis models, as hubs in a Europe-wide system that allocates activities like design and manufacturing to various countries and keeps its accounts in euros. It exports about three-quarters of the cars it assembles in Britain to the other 27 members of the European Union.