A High Court judge gave medics the right to stop baby OT's treatment
Parents battling to keep their seriously ill baby alive have failed to overturn a ruling allowing him to die.
The nine-month-old boy has a rare metabolic disorder and has suffered brain damage and respiratory failure.
The couple had appealed against a judge's ruling on Thursday that it was in the boy's best interests to withdraw his "life sustaining treatment".
They said they were "deeply distressed" by the decision and the life of their "beautiful boy" was worth preserving.
In a statement, they said they knew of only one other child with their son's condition and everyone was in "unknown territory".
"We are and always will be convinced that despite his desperate problems his life is worthwhile and is worth preserving as long as it is possible to do so without causing him undue pain.
"That was the real argument between us and the doctors - they think his life is intolerable and that his disability is such that his life has little purpose; but we, along with some of the nurses, believed that he experiences pleasure and that he has long periods where he was relaxed and pain free.
"Our belief in his humanity and inherent worth justified us taking every step to support him."
They said the plan was now to withdraw his treatment within the next 24 hours and they planned to "enjoy what little time" they had left with their only son.
The High Court ruling gives doctors at an unnamed NHS trust powers to turn off the ventilator keeping "baby OT" alive.
Two Court of Appeal judges refused the couple permission to challenge a decision by Mrs Justice Parker made after a 10-day hearing.
Neither the baby, the trust involved in the case, nor the parents - Mr and Mrs T - can be identified.
Lord Justice Ward was told the couple had decided to wait outside the courtroom while the ruling was given as they could not face hearing the decision.
The judge acknowledged the hearing seeking permission to appeal had been conducted "in a brusque, uncaring, unfeeling way on a crude issue of law".
But he said he would like to have addressed them personally and asked their lawyers to pass on the message that it was impossible not to feel the "deepest sympathy for their predicament".
The NHS trust had argued that the boy was suffering intolerable pain as a result of his treatment and condition and had no prospect of recovery.
His parents, however, wanted him to be kept alive as long as possible. They now have no further right to appeal.
Lord Justice Ward and Lord Justice Wilson said they would give the reasons for their decision at a later date.