The parents of 23-month-old Alfie Evans have lost their latest legal battle even as Catholic bishops in the UK refused to back their case to have the baby taken to the Vatican-run Bambino Gesu hospital in Rome.

The Supreme Court rejected the parents argument that Alfie, who is terminally ill, was being unlawfully detained at Alder Hey hospital in Liverpool. It also denied their right to appeal, meaning doctors can go ahead and withdraw Alfie's life support.

'The unanimous opinion of doctors examining him and the scans of his brain is that almost all of his brain has been destroyed. No-one knows why. But that it has happened and is continuing to happen cannot be denied,' the Supreme Court judges said in their ruling.

It means 'there is no hope of his ever getting better', the judges added.

His father Tom Evans, 21, and mother Kate James, 20, have insisted recovery is possible and want to take him to Rome for further treatment.

Mr Evans met Pope Francis on Wednesday morning this week with the pontiff offering prayers and support.

However Catholic bishops in the UK held back from backing the parents case and said the courts' ruling must be respected.

Bishop John Sherrington said the bishops had a 'deep awareness of the pain' for Alfie's parents.

'It is tragic that parents and the staff are not able to come to agreement. We pray for a coming to agreement for the way forward,' he told journalists on Friday, shortly before the Supreme Court statement was released.

'We saw the pictures of Tom being met by Pope Francis and Pope Francis' prayer for baby Alfie.

'But the way dispute is resolved in this country is through the legal system and therefore if there are other views they must be presented through the legal system.'

He held back supporting the parents' campaign to have Alfie taken to Rome. 'We would want baby Alfie to have the proper, appropriate care for his condition,' he said.

Responding to the Supreme Court's judgment Alder Hey hospital released a statement that said: 'Alfie's parents have done everything in their power to do what they think is best for him even though that is contrary to the views of the doctors. That has inevitably prolonged the period over which he has been given treatment that was determined in February not to be in his best interests.'

It added: 'We understand that this decision is very distressing for Alfie's family at this very difficult time.'

It comes after the Court of Appeal ruled on Monday it was in Alfie's 'best interest' to have ventilation removed and be treated with palliative care. It added that Alfie's best interests, not his parents wishes, were the 'gold standard' which they must consider.

In what appears to be the end of the road for his parents' battle, the Supreme Court's Lady Hale, Lord Kerr and Lord Wilson, reiterated that 'parental rights are not absolute'.

'As we explained in our earlier decision in this case, the best interests of the child are the "gold standard" which is not only adopted by our law but also reflects the international standards to which this country is committed.

'It is therefore clear law that the parents do not have the right to use the writ of habeas corpus to acquire the custody of their child if this will not be in his best interests.'

Monday's appeal judgment criticised the parents' barrister, Paul Diamond, of the Christian Legal Centre, who argued that Alfie's best interest was 'irrelevant' compared to his parents wishes.

'In any context, but specifically in the circumstances of this case, that is a startling proposition,' it said, adding the appeal's argument was 'misconceived'.