Fiona and her husband Mike are the first-ever husband and wife team to conquer the North and South Poles. In January 2004 Fiona returned to conquer the South Pole on a 70-day solo trek. She arrived at the South Pole after 42 days of unsupported solo walking, smashing the previous record of 44 days walking or skiing. This makes her the fastest person to the South Geographic Pole unsupported.

Fiona Thornewill was born and raised in Northamptonshire where she soon proved herself a talented, young athlete. She was particularly gifted at netball, cross-country, 500 metres and high jump. When she left school she studied Hotel Management at college and became an administrator at RAF Newton. It was at RAF Newton that Fiona got her glider pilot's licence at just 23 years of age.

After leaving RAF Newton, she started her fitness centre in Newark and qualified as an instructor too. Fiona now cycles competitively and works as a recruitment consultant.