A survey from the Chartered Institute of Procurement and Supply (CIPS) has revealed that 63% of non-British European companies are planning to stop using UK suppliers.
The research showed a sizeable jump from the 44% figure that was announced in May as businesses grow increasingly concerned by the sluggish pace of Brexit talks between the UK and the European Union.
It also highlighted the fact that one in five British companies are encountering difficulties in securing contracts post-March 2019, which is when the country is due to finalise its exit.
"British businesses simply cannot put their suppliers and customers on hold while the negotiators get their act together," said Gerry Walsh, CIPS’ group CEO.
"The lack of clarity coming from both sides is already shaping the British economy of the future - and it does not fill businesses with confidence."
In response, the Confederation of British Industry has said that two third of British companies will have implemented contingency plans for Brexit by March if a deal hasn't been agreed.