Gwenda Mary Glubb was born in 1894 in Fulwood, Lancashire. Her father, Major General Sir Frederic Manley Glubb, was a senior British Army officer. Her brother John Bagot Glubb would later become famous as Glubb Pasha, commander of the Arab Legion from 1939 to 1956. Gwenda served as an ambulance driver during World War I on both the Russian Front and the Romanian Front from 1914 to 1918, for which she was awarded the Cross of St. George and the Cross of St. Stanislaus and was mentioned in despatches — recognition of outstanding service in extremely hazardous conditions.
Following her marriage to Colonel Sam Janson, a director of the Spyker car company, in 1920, Gwenda took up motorcycle racing at Brooklands. In the winter of 1921 she established the 1,000-mile record on a Ner-A-Car motorcycle, and in 1922 she took the Double-12-hour record at Brooklands on a Trump-JAP. Her close association with Colonel Neil Stewart, who supplied her motorcycles, led to her divorce from Janson in 1923. She and Stewart married and relocated to France, where the unrestricted Montlhéry circuit allowed night racing. At Montlhéry she broke the world 24-hour motorcycle speed record on a Terrot-JAP. In 1930 she recorded 113 mph in a race-tuned Morgan Super Sports three-wheeler.
At Montlhéry, Gwenda met Douglas Hawkes, a director of the Derby engine and car company, who became one of her mechanics. Hawkes sourced a Miller Special from the United States and had it specially prepared as the Derby-Miller. Between 1930 and 1933, Gwenda broke the one-mile speed record several times at Montlhéry in that car. She also competed twice at the 24 Hours of Le Mans in a Derby fitted with a Maserati engine, though with limited results.
In 1935 she set the ultimate mark of her career, posting a lap speed of 135.95 mph at Brooklands, making her the fastest woman ever to lap the circuit and beating the previous record held by Kay Petre. This achievement confirmed her status among the elite of British motorsport regardless of gender.
Her affair with Douglas Hawkes led to her divorce from Stewart, and she married Hawkes as her third husband in 1937.
After the outbreak of World War II in 1940, Gwenda and Douglas Hawkes moved to England, where she worked in an armaments factory. After the war the couple settled on the small Greek island of Poros. Douglas Hawkes died in 1974. Gwenda died on 27 May 1990, aged 95, having outlived virtually all of her racing contemporaries.