Five-year-old brain tumour patient Ashya King may leave hospital in Spain tonight for proton treatment in the Czech Republic.
The director of the Materno Infantil hospital in Malaga, Manuel Paz, told the BBC that Ashya was "ready to leave their care" and "may leave tonight".
However, he added that the boy's departure could be "delayed until the early hours of Monday morning".
A private plane was reported to be waiting at Malaga airport.
The timing of the proposed transfer came as a surprise as doctors in Prague are due to decide in the morning whether Ashya can travel there for the pioneering treatment.
If they opted to receive him following the meeting at the Motol Hospital tomorrow morning, they were expected to send a private medical jet to transport the boy from Spain.
The Proton Therapy Centre in Prague has said documentation from the hospital in Malaga will be reviewed before the child can travel.
Ashya hit the headlines after his parents Brett and Naghmeh King took him from Southampton General Hospital on August 28 without the permission of doctors.
They were arrested and held in custody in Spain after British police raised the alarm. They were released when prosecutors withdrew an arrest warrant in the wake of a public outcry.
The therapy centre's director of strategy, Iva Tatounova, has said no decisions will be taken before the meeting.
"Monday morning at 8 o'clock, in Motol Hospital, the best doctors and oncologic paediatricians will sit down to review this document, and therefore will be able to say, yes, he's capable of travelling to Prague," she told Sky News.
"We have to follow the standard procedures, which, if he comes on Monday night or Tuesday night or even Wednesday night, this doesn't make any harm to him, and the family can feel okay.
"Proton therapy will be part of his treatment. If he receives chemotherapy or not, this decision has to be made by Motol clinical oncologists, we don't do chemotherapy here."
Portsmouth City Council, which has responsibilities for Ashya's welfare, launched family court litigation - asking for directions about the youngster's treatment.
Mr Justice Baker began analysing issues surrounding Ashya's treatment at a hearing in the Family Division of the High Court on Tuesday. The judge was told Mr and Mrs King wanted their son to receive proton beam radiotherapy.
The judge said in his order, released on Friday, that Ashya could be taken to the Czech Republic. He said he had been told specialists there had considered a treatment plan.
The hospital has said Ashya is in a stable condition, and that a flight to Prague would not pose a problem to his health.
Family lawyer Juan Isidro Fernandez Diaz told reporters the boy was "in perfect condition to travel", and was playing with toys and his parents and brother yesterday.