He went on: "To be fair to the authorities involved in the case of Ashya King, they all want to do the best for the child. That is what they are thinking of. But I think what happened was that decisions were taken that weren't correct and didn't chime with a sense of common sense. That fortunately has been put right.
"What all of us in public life and public offices have to do is examine what the legal requirements are but also make a judgement. Those judgements can sometimes be all important."
Later in the session, Liberal Democrat John Hemming (Birmingham, Yardley) said British families - like the Kings - were increasingly leaving the UK because they believed they would get a fairer trial in the family courts abroad.
He called for Parliament to be allocated time to look at the reasons for this.
Mr Cameron replied: "We do regularly debate in this House family law. This Government has made some amendments to family law after long debate within the Government and in this House."
Earlier, Jacob Rees-Mogg criticised the way the EU arrest warrant had been used by Hampshire Police in the Ashya King case, calling it an "injustice".
