Nick Clegg has said he believes it is “not appropriate” to “throw the full force of the law” at the parents of five-year-old brain cancer patient Ashya King.
The Deputy Prime Minister said his “heart goes out” to Brett and Naghmeh King after they spent another night away from their son.
His comments come amid growing calls demanding their release from detention.
The couple, who were arrested in Spain after Ashya was taken from a UK hospital without doctors’ consent, told a judge in Madrid that they do not want to return to the UK.
The judge ruled that they must be held for up to 72 hours while the court considers whether to grant a British extradition request.
Mr Clegg told BBC Breakfast: “My heart goes out – and I’m sure every mum or dad will have the same response, which is, as far as I can make out, this is a family in a state of real anguish who have taken this exceptional step of moving their sick child to another country because they think that’s what is best for their child.
“We can debate whether it is or is not but that seems to be their motive and those are not motives I can argue with.
“That’s why I personally think that throwing the full force of the law at Mr and Mrs King, who appear to be doing what they believe to be best for their own family, I don’t think is an appropriate thing to do. But that, at the end of the day, is for the police and the CPS and others to decide.
“But that’s my personal view and I do hope for that reason it’ll be resolved.
“A little boy is on his own in a hospital, doesn’t speak Spanish, is cut off from his parents and his siblings and I would like to see him together with his family as soon as possible.”
The boy is being treated in a hospital in Malaga and his grandmother and brother have criticised the way his parents are being treated.
The family took him from Southampton General Hospital last Thursday and travelled to France with him and his six siblings before heading to the Costa del Sol in southern Spain.
Mr King, 51, and his 45-year-old wife were arrested in Velez-Malaga on Saturday night.
More than 80,000 people have signed an online petition demanding Ashya is reunited with his parents.
Mr Clegg told ITV’s Good Morning Britain: “I’m sure the CPS will be conscious of the opinion of people like me in Government but of the public generally which say, look, let’s set aside for a minute whether that was the right thing medically for Ashya or not but at least keep the family together and let them act as a family because, as far as I can see – I don’t know them of course myself – but as far as I can see, Mr and Mrs King are acting in what they believe is the best interest of their own child.”
Ethan Dallas, a friend of Ashya’s brother Naveed, told the programme he will take the petition containing nearly 100,000 signatures calling for the family to be reunited to Downing Street later.
He said: “I think that he (David Cameron) just needs to release Brett and his wife and allow them to choose the treatment that they see fit for their son.”
Mr Dallas said the family are “really stressed”.
He said: “I’ve spoken to Naveed on Skype and he’s said that they are all super-stressed, they’ve barely slept at all and they’re just really, really hoping to see their little brother really soon.”