Japan warned Prime Minister Theresa May on Thursday that its companies would have to leave Britain if trade barriers after Brexit made them unprofitable.
"What Japanese businesses in Europe most wish to avoid is the situation in which they are unable to discern clearly the way the Brexit negotiations are going, only grasping the whole picture at the last minute".
Britain and Japan have established deep rooted trade ties spanning a breadth of business sectors, from the automotive industry and machinery, to pharmaceuticals and retail.
"I'm sure the PM will be reiterating that when she meets the companies today, and also the commitment to securing an implementation period as soon as possible to give them a period of time to adjust to the new relationship that we are going to build with the European Union". "This is all high stakes that I think all of us need to keep in mind", he said.
They will be joined by some of Japan's biggest banks - Nomura, Mizuho and Sumitomo Mitsui Banking Corporation - all of which have a significant presence in the City of London.
"Uncertainty is a major concern for an economy", it said.
Both London and Brussels hope to agree a transition deal lasting until the end of 2020, in which Britain would remain in the single market and be bound by all European Union laws, by a March 22-23 summit.
Last year, Soros suggested the United Kingdom may never leave the European Union if the bloc reforms itself while Brexit negotiations are taking place. May's Cabinet is divided between those who want to remain close to the single market and customs union and those who want a clean break.
"What we're about is building an implementation period, which is to build a bridge to a future where we work well together", said Brexit minister David Davis.
Nissan, Toyota and Honda began their United Kingdom operations in Britain in the 1980s and now build almost half of all of Britain's 1.67 million cars.