Britain’s North Sea oil plummeted to $8.50 a barrel.

The price dropped amid concern over an unexpected rise in U.S. gasoline supplies during the summer driving season, when motorist demand should be at its peak. On the European spot market, where oil is sold to the highest bidder, Britain’s Brent crude fell by 75 cents to a record low of $8.50 a barrel. The previous historic low for the benchmark North Sea crude was $8.65 a barrel, hit July 15. Britain began selling oil in 1976 at an official price of $12.60 a barrel.