LONDON (AP) — British prosecutors are dropping the case against a couple who ended up in a Spanish jail after they tried to get treatment abroad for the boy's severe brain tumor, authorities said Tuesday.

Brett and Naghemeh King were pursued by police after they took 5-year-old Ashya out of a hospital in southern England against doctors' advice and traveled to Spain, where they planned to sell a property to pay for proton beam radiation therapy in the Czech Republic or the U.S. They were arrested on a British warrant on suspicion of cruelty to a person under 16 years of age, and are in custody in a jail near Madrid — while their son is in a hospital in Malaga.

"No further action will be taken against Mr. and Mrs. King and we are now in the process of communicating this decision to the Spanish authorities," British prosecutors said in a statement, adding they were doing it so the family can be reunited as soon as possible.

The case has riveted Britain, with heated debate as to whether authorities acted appropriately in chasing the parents through Europe after they left Southampton General Hospital last week without the consent of doctors.

Prime Minister David Cameron took the highly unusual step of wading personally into the debate, tweeting that he welcomed the prosecution against Ashya's parents being dropped.

"It's important this little boy gets treatment & the love of his family," he wrote.

Police said the arrest warrant was applied for so that Ashya could be found as soon as possible, but the situation is now "not right."

"Our intent was to secure his safety, not to deny him family support at this particularly challenging time in his life," Hampshire Police chief constable Andy Marsh said.

Earlier in the day, Cameron told the radio station LBC that the plight of Ashya reminded him of his late son Ivan, who had cerebral palsy and epilepsy. The prime minister recalled having his own son sit on his lap and feeding him through a tube.

A Spanish court spokesman declined immediate comment on when the parents could be released, but a lawyer for the couple said the judge has the options of releasing them immediately or having them stay overnight in jail to be released at the previously-scheduled court hearing at 11 a.m. (0900 GMT, 5 a.m. EDT) Wednesday.

"The only reason for them to stay in prison has expired," lawyer Francesco Luca Caronna told The Associated Press. "If the system works, they should open the doors to the jail immediately."

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Associated Press writer Jorge Sainz contributed to this report from Madrid.