LONDON — Britain will transfer £43 million to the U.S. Treasury on Friday, the final payment on a debt used to finance the World War II defeat of Adolf Hitler and Nazi Germany.

The U.S. extended $4.34 billion in credit in 1945, allowing Britain to stave off bankruptcy after devoting almost all its resources to the war for half a decade. Since 1950 Britain has made payments on the debt, the final payment of which is worth $84 million, at the end of every year except six.

At the time it was granted, the loan strained trans-Atlantic relations. British politicians expected a gift in recognition of the country's contribution to the war effort, especially for the lives lost before the United States entered the fight in 1942.

"The U.S. didn't seem to realize that Britain was bankrupt," said Alan Sked, a historian at the London School of Economics. The loan was "denounced in the House of Lords, but in the end the country had no choice."