Doctors who treated brain cancer sufferer Ashya King in Britain yesterday accused the boy’s parents of putting his life at risk when they refused to let him have chemotherapy. Consultant Peter Wilson told a BBC TV documentary Ashya’s chances of long-term survival could have been halved by Brett and Naghmeh King’s decision to flee abroad with him before he had the treatment he was being offered here. Dr Wilson, clinical director for child health at Southampton General Hospital, claimed the chemotherapy was essential to reduce the chances of the five-year-old’s cancer returning. Scroll down for video . Clinicians in an ‘impossible situation’ as a result of King family’s flight to Spain after disagreeing with doctors . And in an interview on Radio 4’s Today programme he complained of the ‘vitriol’ to which he had been subjected as a result of the case, saying: ‘I personally received a letter from a person who said they wished my children got cancer and died.’ Mr and Mrs King had accused the hospital of planning treatment which would have left their son a ‘vegetable’ and took him abroad last year for proton beam therapy, an alternative form of radiotherapy. Mr King, 51, said Ashya did not need subsequent chemotherapy as his cancer was in remission. Last month, four months after the proton treatment ended, the family said scans showed ‘no evidence’ of the tumour. But Dr Wilson, a paediatric intensive care consultant, said Ashya should have undergone chemotherapy within six weeks of his original surgery to remove the tumour in Southampton last July, and said it was too early to say he had been cured. He told the BBC: ‘We are unsure as to exactly what treatment he is receiving but what we do know is… every month that goes by that he’s not getting chemotherapy, his outcome worsens. The family then went to Prague for proton beam therapy, and now say there is 'no evidence' of a tumour . ‘There are experts in the country that have already quoted figures of halving survival – so survival going from 80 per cent to 40 or 50 per cent, which is quite dramatic.’ Dr Wilson said there was an ‘international consensus’ of medical opinion that Ashya’s form of brain cancer should be treated by surgery followed by chemotherapy and radiotherapy. After he had the surgery in Southampton his parents took him from the hospital without telling doctors. He was eventually given radiotherapy in the form of proton beam therapy in the Czech Republic, but his parents said the chemotherapy was not needed. They initially fled to Spain where they were arrested then released after the High Court approved their plan to take Ashya to Prague. The NHS eventually agreed to pay for the proton therapy there. Dr Wilson said there was a risk that tiny cancerous cells remained around the tumour site after the surgery, and that chemotherapy and radiotherapy were required to treat those cells to offer the best possible chance that the cancer would not return. The Kings were unavailable for comment but have said they wanted Ashya to receive the best possible treatment. Paediatric intensive care consultant Dr Peter Wilson said it was 'deeply unfair when the NHS is supposed to be about equal healthcare for all’ that he had to say no to parents wanting proton beam therapy for their children .
Doctors and nurses have criticised Ashya's parents in BBC documentary . Dr Wilson claims chemotherapy was essential to reduce chances of five-year-old’s cancer returning . Complained of ‘vitriol’ to which he had been subjected as a result of case . Consultant warns case - which saw parents ignore medical advice to take Ashya to Prague for proton beam therapy - could set a worrying precedent .