George Best was unconscious and breathing with the help of a ventilator last night.
"I am afraid Mr Best is coming to the end of the long road of his ill health," said his consultant, Prof Roger Williams.
The ex-Manchester United striker's family, including son Calum (24) and father Dickie (87), kept a vigil by his bedside, and former team mates Bobby Charlton and Denis Law came to say emotional goodbyes.
It was also revealed that Best, who received a controversial liver transplant in 2002, carries a donor card and his organs will be made available to help others live.
Prof Williams, who has overseen Best's treatment, left the private Cromwell Hospital in west London last night, saying: "There is no change, just deterioration." Earlier, Prof Williams was close to tears as he announced outside the hospital that Best was about to die.
"He is still alive, he is still having standard medical care and treatment, but I have to tell you that his hours are numbered now.
"I can't be precise as to time but it is the final stages of this illness and I am afraid he could die at any time over the next 24 hours. I would be very surprised if he survives another 24 hours."
The former Northern Ireland star had a liver transplant after his own failed following years of alcohol abuse.
Best, who ignored pleas to stay off alcohol after the operation, was admitted to the Cromwell on October 1st suffering from a flu-like infection.
His health deteriorated rapidly when he developed a kidney infection, but he then rallied and his condition was thought to be improving until the early hours of Friday, when he suffered a severe setback.