A heartbroken Paula Radcliffe has revealed the extent of her despair after her dreams of making up for previous bitter Olympic disappointments on home soil were extinguished.

Radcliffe today formally withdrew from the women's marathon at London 2012 after admitting defeat in her battle against a degenerative foot problem, which cruelly resurfaced just a few weeks ago.

The 38-year-old had been hoping to claim a first Olympic medal in her fifth Games, having finished fifth in the 5,000m in Atlanta, fourth in the 10,000m in Sydney and suffering despair in the marathon in 2004 and 2008.

In Athens, Radcliffe was an overwhelming favourite but was forced to drop out less than five miles from the finish after a debilitating stomach problem, while in Beijing the after-effects of a stress fracture of the femur saw her finish a lowly 23rd.

Although her Olympic career is now over, Radcliffe insists she will carry on running as UK Athletics head coach Charles van Commenee urged people to remember she remains the world record holder for the marathon and was world champion over the distance in 2005.

"I have been through the mill emotionally and physically the past three weeks, cried more tears than ever, vented more frustration and at the same time calmly tried every direction and avenue available to heal myself," Radcliffe said. "Now is the time to rest totally, give my body chance to recover and assess calmly what can be done and where I go from here.

"It is hard to know that had the Olympics been six weeks earlier I could have gone out there and run confidently knowing that I was in the best shape I had been in for a while, but I am by no means the first to experience something like this. No-one tells us in advance where the limits of our own bodies lie, and pushing these limits is the only way we can ever achieve our highest goals and dreams.

"As desperate as I was to be part of the amazing experience of the London Olympics, I don't want to be there below my best. If I can't be there and give it my best, then I would rather someone else who can do that is able to be there."

That person will be Scotland's Freya Murray, assuming her nomination as a late replacement is approved by the International Olympic Committee. Murray was just beaten to the last available place on the team by Claire Hallissey at the Virgin London Marathon in April.

Radcliffe easily achieved the Olympic qualifying time in Berlin in September last year, but was then "at a loss" to explain her slowest ever half-marathon time in Vienna in April, her only race in 2012.

She added: "From the day when it was announced that London had won the bid, taking part and performing well in the London Olympic Games has been a major goal in my life.

"The goal of a fifth Olympics in my home country, what better? The chance to make amends to myself for bitter disappointments at the previous two Olympics. Through a lot of tough times it has kept me fighting, motivated and focused. That is why it hurts so much to finally admit to myself that it isn't going to happen.

"My sport is a beautiful sport, it gives so much fun and enjoyment, I believe it helps me to be a better person and I have been very fortunate to experience some great success and have so many beautiful and happy memories.

"However, the downside is that it can break your heart and spirit many times over when your body is simply unable to match what your heart and brain want it to do. Sadly mine is not a career or a hobby where mind over matter can work when your body is hurt, nor where giving less than your best each day can ever work.

"Yes I made more commitment than ever in preparation this year, two months away from the three most important people in my life (her husband Gary and children Isla and Raphael).

"However, every single athlete out there makes the same commitments, puts their all into their preparation, and sadly I am not the only one to suffer heartbreak in trying to go after our goals. The most important thing is, as I always believe, to know that you did all you could in going after those dreams.

"However hard today is, finally closing the door on that dream, at least I can know that I truly have tried absolutely everything. Not one day was wasted in getting treatment, scans or interventions that might help.

"I cross-trained as hard as I could whenever I was unable to run to give myself every chance should the pain settle. Now however, is the time to accept that it is just not going to settle in time."

Paying tribute to Radcliffe, Van Commenee said: "This is obviously a disappointing day for Paula and our sport, but it was important to her that if she made the start line it would be in the best possible shape. It wasn't meant to be and she has taken the right decision to withdraw at this stage.

"I think it is important that we don't look at Paula's career in Olympic cycles. She is undoubtedly one of the greatest female distance runners of all time and still holds the marathon world record.

"When we look back at her career it should be in the context of what she has achieved and not what she hasn't. I wish her all the very best for her recovery."