(CNN) -- Record-holder Paula Radcliffe has decided against trying to win back her marathon title at the World Athletics Championships in Berlin on Sunday.
Marathon record-holder Paula Radcliffe is still hoping to compete at the 2012 Olympics.
The 35-year-old has pulled out of the British team despite her victory in last weekend's New York City half-marathon, which was supposed to test her fitness following her return from foot surgery.
"I am devastated that I wasn't able to be ready in time to represent Britain here in Berlin, especially having got so close in such a short time-frame," Radcliffe, who won the world title in 2005, said in a statement on the UK Athletics Web site.
"However, after having the surgery to successfully put the years of injury behind me, it is very important to me that I come back to racing often and winning at 100% and continue strongly and successfully through to London 2012.
"It has been great to be here and to spend time with the team, which has performed so well so far, and I look forward to being part of it again in the near future.
"Running in New York this weekend was a necessary part of the process to ascertain my race fitness and after speaking with my coaching and medical team, I knew I was sadly just not quite ready."
Radcliffe missed the 2007 championships after falling pregnant with her first child, and then suffering back problems.
She battled to be fit for the Beijing Olympics after breaking her leg, but could finish only 23rd as she suffered from cramp.
"To lose an athlete of Paula's caliber is disappointing to say the least," said UKA head coach Charles van Commenee.
"She won the World Championships in 2005 and a fit Paula would clearly be in contention to regain that title, but she has taken that difficult decision and we have to respect that."
Great Britain has had one of its most successful championships so far, with Phillip Idowu winning the triple-jump to make up for his silver at the Olympics, while Jessica Ennis claimed gold in the women's heptathlon.