She was the 1500 m bronze medallist at the 2002 Commonwealth Games.
She achieved the Olympic A qualifying standard for the 3000 m steeplechase at the Meeting Iberoamericano, in Huelva on 13 June 2008, where she finished eighth in a time of 9:43.56.
Her place in the British team for the Games was confirmed when she won the British trials in a new national record time of 9:36.98.
At the Games she finished sixth in her heat and did not advance to the next round of competition, despite beating her own national record with a time of 9:29.14.
At the 2008 IAAF World Athletics Final, in Stuttgart, Clitheroe placed 9th in the 3000 m steeplechase in a time of 9:39.72.She completed a spell of high-altitude training in Iten, Kenya and then came close to a 3000 m lifetime best at the Aviva International Match in January 2011, finishing with a stadium record run.
The May 2011 Great Manchester Run saw her produce a career best for the 10K as she completed a dominant performance to win the race in a time of 31:45 minutes.
She set herself a similar target at the European Cup 10000m in June 2011, but suffered in hot conditions and finished in fourth with a time of 32:11.29 minutes.