Aljaz Bedene is to switch his allegiance back to Slovenia despite becoming a British citizen in 2015.
The world number 49 will play for the country of his birth again next year in order to compete at the 2020 Olympics.
New International Tennis Federation (ITF) rules mean he is not permitted to play for Britain in the Olympics or Davis Cup.
Bedene, 28, who was British number two, said he does not want to miss out on “two events that mean so much to me”.
His plans to represent Great Britain were thwarted by the ITF’s decision, with little notice, to prevent players representing more than one country from January 2015.
“I have proudly called Britain my home for the last nine years and so many people there have made me feel welcome both in the UK and abroad,” Bedene said in a statement on Friday.