Sally Robert, 37, did not want her son Neon to have radiotherapy and wanted to look into other methods of treatment, such as immunotherapy and photodynamic therapy to treat him.

But judge Mr Justice Bodey said any further delays could be harmful and refused to adjourn the case for her to call evidence for other methods, as it was not in her son’s “best interests”.

Counsel for the hospital trust treating Neon said the child should not be subjected to “experimental therapies” and “unproven treatments”.

Bodey ordered that Neon underwent an emergency operation, which took place on Wednesday, against his mother’s wishes.

Robert said she wanted more time because she was “not persuaded of the need and not persuaded of the urgency” of surgery, and wanted a second opinion.

Medical practitioners treating Neon said it was “highly, highly, likely he would die over a relatively short period of time”, which led the judge to order an operation.

Roberts was persistent to change the ruling, seeking an appeal at the court of appeal at 12:30am on Wednesday morning, just hours before the operation was due to go underway.

Her appeal failed.

On Thursday surgeons told the judge they “found evidence of a tumour nodule” which was “consistent with medulloblastoma”. They felt no obvious tumour was left behind, but that therapies such as radiotherapy and chemotherapy were required “because of the risk of microscopic tumour being left behind”.

Neon was now “standard” rather than “high risk”.

Roberts made headlines when tried to prevent Neon having radiotherapy when she disappeared with him for four days earlier this month.

Doctors want to start radiotherapy by 9 January, and no later than 16 January.

The court heard that Roberts prevented her son from taking anti-hermetic drugs, used to control nausea, after the operation.

Roberts’s representative, Ian Peddie QC said: “The mother remains concerned that radiotherapy is not in [Neon’s] best interests.”

Robert wanted more time so she could submit evidence of other treatments, after being given a list of alternative methods from “Dr V”, who cannot be named.

Victoria Butler-Cole, representing the hospital trust, opposed further delays and said it was clear that Dr V “was not familiar or remotely expert” in the treatment of medulloblastoma. The disease medulloblastoma “is spelled wrongly” and his description of it was taken from the internet or newspaper cuttings.

Cole said the list included one doctor’s website that described using “herbs, nutritional supplements, enzymes, diet and psychological healing strategies in treatment for cancer”.

She compared this treatment to “a hospital and centre of excellence that offered the gold standard treatment being offered to all other children in this country who have this disease”.

Butler-Cole said: “The dose of realism that is required is whatever these doctors may be prepared to say or prepared to, provided funding could be found from a private source, the prospect of the court accepting their views in preference to the gold standard in this country is so small as to enable the court to take a robust approach to the mother’s position today.”

Roberts’s application to have the case adjourned until early in January was denied by the judge.

On Tuesday, Roberts fired her original legal team because she lost confidence in them, the court heard. Human rights lawyer Imran Khan, and Ian Peddie QC now represent her.

The case continues.