Neufville first appeared on the international scene in September 1969, when she ran the 4×400 m in a Great Britain vs West Germany match in Hamburg.

This caused wide controversy with many members of the British public saying she had betrayed where she was trained and considered her switch like treason.

[citation needed] At the Commonwealth Games, Neufville established a new world record by improving the preceding mark previously held by the Frenchwomen Colette Besson and Nicole Duclos with 51.0 s (electronically timed as 51.02 s)[3] at the age of 17.

In 1970, she gained more recognition at ISTAF athletics meet in Berlin then at the AAA championships running 52.6 s in front of Germany's Christel Frese and Inge Eckhoff.

[5] After battling with injuries, Neufville returned at the 1974 British Commonwealth Games but was a shadow of her former self—only finishing sixth in the 400 m final.