Olympic 400m hurdles bronze medallist Tasha Danvers will miss next month's World Championships after failing to recover from a hamstring injury.
The 31-year-old had been receiving treatment since picking up the injury during a contest in Cardiff.
"I'm disappointed I'll be unable to compete in Berlin, but I have simply run out of time, " said Danvers.
"The most important thing for me is getting back to full health and come back stronger for 2010 and beyond."
Danvers came to her decision following her most recent consultation with UK Athletics chief medical officer Dr Paul Dijkstra.
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