Five-year-old Ashya King was last night being readied to travel from Spain to the Czech Republic for treatment on his brain tumour.
Health officials in Malaga met Ashya's parents, Brett and Naghmeh King, and agreed that the transfer could take place as the boy was deemed to be in a stable condition.
The director of the Materno Infantil hospital in Malaga, Manuel Paz, told the BBC last night that Ashya was "ready to leave their care" and "may leave tonight".
A private plane was reported to be waiting for the child at Malaga airport.
He was due to fly to Prague so he can be treated with proton beam technology, which his parents believe is the best option, but which was not offered to the little boy by doctors in the UK.
The timing of the proposed transfer came as a surprise as doctors in Prague were only due to decide this morning whether Ashya could travel there for the treatment.
The Proton Therapy Centre in the city has said documentation from the hospital in Malaga will be reviewed before the child can travel.
The therapy centre's director of strategy, Iva Tatounova, added that a final decision would be taken this morning on whether Ashya is able to fly.
"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," she added.
Family lawyer Juan Isidro Fernandez Diaz told reporters the boy was "in perfect condition to travel".
He added that Ashya was playing with toys and his parents and brother yesterday.
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 that 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 added he had been told specialists there had considered a treatment plan.
Ashya hit the headlines after British police raised the alarm when his parents took their son from hospital on August 28.
Brett and Naghmeh King were initially arrested by Spanish police after they removed Ashya from the hospital in Southampton and drove him to Malaga in their search for specialist treatment he would not get in the UK.
They were later released after charges against them were dropped.