Reality television star Jade Goody has been criticised by London Marathon organisers for failing to train properly for the 26.2-mile (42km) race.
Jade was among 700 runners who failed to finish the course
The Big Brother celebrity, running for children's NSPCC charity, is thought to have dropped out after 18.5 miles.
Ms Goody has said she "got bored" with training and had instead been "eating curry and Chinese, and drinking".
Marathon director David Bedford said it was "almost at times suicidal" to start the race without adequate preparation.
"We, of course, recommend that everyone that takes part in the marathon trains, and to start by thinking I'm just going to walk round and not even be able to walk a marathon clearly shows she's done nothing and is not in good shape," he told LBC News.
Race organisers said it was assumed Ms Goody, 24, had not completed the course.
She reached the 18.5-mile point of the course in four hours and 37 minutes but there was no further record of her.
The NSPCC said Ms Goody's sponsors have indicated they will still be honouring their pledges.
Stephen George, NSPCC director of community appeals, said the charity's 350 runners are provided with support and advice about training and nutrition.
Ms Goody had not attended a reception the charity puts on after the marathon, he added.
"Jade approached us and offered to run for us, and we are really grateful for that," he said.
"We have enjoyed having her supporting us and we are hopeful she is OK and well."
Some 90,000 people applied for one of the 34,500 places in the 26th London Marathon. More than 700 other runners failed to finish.
Bookies William Hill are already offering odds of 2-1 that Ms Goody will finish the 2007 race.