It was the latest — and possibly most frustrating — setback in a long list of Olympic disappointments for Radcliffe, one of the best female distance runners ever who holds the marathon world record but has failed to win a medal in four previous games.
In London, she won't even make it to the start line after a lingering left foot injury flared up during training over the past month.
"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 in a statement. "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."
The 38-year-old Radcliffe failed to finish the 2004 Athens Olympics marathon and was 23rd in Beijing four years later after deciding to race while still recovering from a stress fracture in her thigh. She finished fourth in the 10,000 metres in Sydney in 2000 and was fifth in the 5,000 in Atlanta.
She is a three-time winner of the London Marathon, and had hoped for one more big victory in the British capital.
"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," Radcliffe said. "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."
She said the joint in her injured foot is "degenerative and badly damaged" but not the end of her career.
"I don't believe now that it can't recover and be carefully managed to allow me to still do what I love to do," she said. "Unfortunately though, that isn't going to happen in one week."
She has been plagued by injury problems since winning the world championship in 2005, with back, hip and toe complaints curtailing her competitive action and denying her a marathon triumph since 2008.
"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," she said. "I cross trained as hard as I could whenever I was unable to run to give myself every chance should the pain settle."