Britain's Tasha Danvers, a bronze medalist in the 400m hurdles at the 2008 Beijing Olympics, announced on Sunday that she was retiring from athletics.
Danvers has struggled with a series of injuries, missing the 2009 world championships and most recently sidelined with an Achilles problem, but was still hopeful of making an appearance at the London Games which starts on July 27.
"It's extremely disappointing not to be able to put myself into contention for selection for London 2012," the 34-year-old said in a statement.
"Based on my training at different stages my coach and I believed we had a genuine chance of making it. But the setbacks have been too many to overcome. Sadly my body has had enough."
(Reporting by Matt Barker, editing by Pritha Sarkar)