By Clare Murphy
BBC News health reporter
After three days in intensive care Oluchi was breathing on her own
A two-year-old girl has made an almost complete recovery after spending nearly 20 minutes at the bottom of a pool.
Scans showed Oluchi Nwaubani had been starved of oxygen for some 18 minutes - three times longer than the brain can usually survive - in Bromley, London.
Despite being warned that even if she were to live she may never walk or talk again, her parents say she can run around and say "what she wants".
Doctors say while the case is highly unusual, it is not unprecedented.
Prompt response by both ambulance and helicopter to the scene of the accident in south London last September may well have made the difference between life and death.
Oluchi was rapidly airlifted to the Royal London Hospital in Whitechapel before being transferred for specialist care to Great Ormond Street - after three days she was breathing again on her own.
As well as the rapid, high level of intensive care Oluchi received, her youth combined with the cold water may also have helped her beat the odds.
"Contrary to popular belief small children are quite strong - they have very healthy hearts, lungs and brains," says Ffion Davies, an A&E consultant and member of the Royal College of Paediatrics and Child Health.
"On top of that, the cold water will have slowed down the body's metabolism and so you can actually survive quite a long period without oxygen."
Children cool faster than adults because they have a higher ratio of surface area to weight than adults.
Oluchi's case may be unusual but there have been several such cases of both children and adults surviving prolonged periods under water in recent years.
Last year, a 35-year-old London architect was found floating in the water off Cape Town: when dragged to shore he was not breathing and had no pulse.
While it is not clear how long John Deeks spent under water, it is thought he was without a pulse for as long as an hour.
Cool water is thought to have played a part in his survival - the water he was swimming in was likely to have been around 15C (60F).
There have also been a string of cases documented in the US. Oluchi's case is put into perspective by that of Michelle Funk, who was also two when she was submerged in a cold Utah river for nearly 70 minutes in 1986.
Doctors published an article on her progress in 1988, by which time she had essentially returned to normal.
Three months on from the accident, Oluchi's parents are hopeful of a full recovery. They say movement is currently the main problem.
"Nevertheless she is now on her feet - she's walking, she's running, and her speech is very good," says her mother, Tayo.
"She's all over the place. You can't keep her down."