In 2008 Purdue did not improve her position at the 2008 IAAF World Cross Country Championships, ending the junior race in 16th place, but remained the top European performer. She made her senior international debut for Great Britain and Northern Ireland in 2008, running a 5 km leg of the Chiba Ekiden Relay in Japan and helping the team to seventh in the rankings. She improved one place further at the 2008 European Cross Country Championships, taking the silver medal behind Twell in a British-dominated race which saw the country take the top six positions in the junior race.