Seven-year-old Neon will have radiotherapy treatment, following surgery on a brain tumour, against his mother's wishes.
Specialists treating Neon accepted that there were side-effects to radiotherapy but said that without the treatment the youngster could die within a few months.
Mr Justice Bodey, who heard evidence at a hearing in the Family Division of the High Court in London, said radiotherapy treatment could start.
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A remarkably mild night with misty low cloud on the hills of Scotland, Wales and north-west England and further rain in places.