As an adult, her roles have included Crystal in the American action film Resident Evil: Afterlife, and Katie Sutherland in British comedy The Inbetweeners.
In 2000, Barnfield won the role of bully Maddie Gilks in Grange Hill, in which she found herself in central plots during her four years on the series.
[5] After Grange Hill, Clarke filmed Popcorn with Jodi Albert and Jack Ryder, and plays the character of Yukino.
Other roles include Zoe Stringer in Filthy Rich, in which she plays the daughter of Mike Reid's character shortly before the actor died; The Bill, in which she played Chloe Fox for three episodes in 2004 and Kelly Burgess in October 2007; and Casualty, in which she appeared as Claudie Waters for two episodes on 29 and 30 December 2007.
In 2011, she played the lead role of Kate in Johannes Roberts' Roadkill, a horror film about a group of teens taking an ill-fated RV trip around Ireland.