Parents of UK's first sextuplets in 17 years were plunged in grief as they lost one of the babies, and were praying for the survival of the other children who were born premature.
Vicky and Andy Lamb, who were overjoyed at the birth of six children on May 14, had been keeping a vigil in a neonatal intensive care unit.
But last night their spokesman Max Clifford, said that one of the boys had passed away.
"They are hoping and praying that the others were going to survive," Clifford said.
The Lambs, who are both 31 and run their own company specialising in health and safety, conceived the four girls and two boys with the help of fertility treatment and, despite the risks were said to have been "thrilled" to be expecting sextuplets.
The children were born 14 weeks early.
The Lambs have a five-year-old daughter, Gracie, who was also conceived using Clomid, a fertility drug.
The tiniest of the babies, born last Friday weighed under 1 lb 5 oz and the biggest just 1 lb 15 oz.
The new arrivals were under the close care of experts in the neonatal intensive care unit of Oxford's John Radcliffe Hospital.
Live births of such a high number of babies are rare and the birth of sextuplets is believed to occur in just one in every 4.5 million pregnancies.
The siblings are dependent on an array of medical equipment and the devotion of experts for their survival.