American Freddie Spencer won the 500cc division...

American Freddie Spencer won the 500cc division of the British motorcycle Grand Prix hours after clinching the 250cc world championship with a fourth-place finish at Silverstone, England.

The 23-year-old rider from Shreveport, La., led from the first bend of the 28-lap, 82-mile 500cc race in atrocious conditions to virtually secure the world title and a unique double.

Spencer can clinch the 500cc title in Anderstorp, Sweden, next weekend to complete a unique double in motorcycle racing. No other rider has won the 250 and 500cc titles in the same year.