The parents of a boy with a rare genetic condition are to learn the outcome of their High Court fight over the NHS's decision to refuse funding for a "life-changing" drug.
The seven-year-old, identified only as S, has severe autism and phenylketonuria (PKU), which inhibits his ability to digest protein.
His autism affects his ability to comply with the dietary restrictions which form the standard treatment for PKU, so his doctors sought funding for a drug called Kuvan.
Last month, S's counsel, Ian Wise QC, told Mrs Justice Andrews - who will give her ruling in London on Tuesday - that funding had been repeatedly refused by NHS England with differing reasons given, leaving S at risk of the consequences of poorly controlled PKU, including brain damage.
He said the decision to refuse funding should be quashed as it was "irrational, unreasonable and unlawful", as well as contrary to the 2004 Children Act and Article 8 of the European Convention on Human Rights, which covers private and family life.
S's father has branded the decision "extremely frustrating, unfair and inhumane".
"No family should have to fight with the NHS for over 18 months to ensure that their child is given proper treatment.
"It is clear to me they do not want to fund this life-changing drug."
Jenni Richards QC, for NHS England, said there was no basis for impugning on rationality grounds the judgements reached as to clinical and cost effectiveness or equity of funding.
NHS England had a policy, which was unchallenged, not to commission Kuvan because of insufficient evidence as to its medium and long-term clinical effectiveness.
The mainstay of PKU treatment was - and would remain, even with Kuvan - dietary control.
She said that S's consultant acknowledged that, in terms of neurological impairment, his overall development outcome would mostly be affected by the severity of his autism rather than his PKU.
He also accepted that Kuvan would not be expected to significantly alter or improve S's behaviour.
Any order compelling NHS England to fund S's treatment would be wholly wrong, she added.
"The court's function is to consider the lawfulness of NHS England's decision-making.
"It is no part of the court's function to allocate scarce NHS resources or to take decisions about the equitable division of those resources."