Justin Stebbing is facing a fitness to practise hearing over claims that he failed to provide good clinical care to 12 of his patients.
The Imperial College London professor, who also has a private practice in Harley Street, has a reputation for innovative treatments.
He has cared for famous names including chat show king Sir Michael Parkinson and late actors Sir Roger Moore and Lynda Bellingham.
The 36 accusations against Prof Stebbing include not keeping proper records and failing to gain informed consent for treatment from patients between 2014 and 2017.
He has admitted 21 of the allegations and is appearing at a hearing of the Medical Practitioners Tribunal Service (MPTS) after his case was referred by the General Medical Council (GMC).
But leading oncologist and Daily Express columnist Professor Karol Sikora, an expert witness called for Prof Stebbing, said it was Britain’s approach to cancer care which ought to be put under the microscope.
The former cancer adviser to the World Health Organisation told the Manchester hearing the UK was “far behind” on the global cancer league table because of “overly strict” adherence to guidelines at the expense of clinical judgment.
He said: “I don’t know why this is involving the GMC. You’re pillorying him [Prof Stebbing] through no fault of his own.”
Prof Sikora also questioned the length of time and the cost of the MPTS hearings, saying: “The whole system has been let down by the GMC.
“I pay £450 a year to the GMC. The case runs on. A delay of four years is unacceptable.”
Prof Sikora also argued that the 12 cases cited had been selected over thousands of other patients Prof Stebbing had treated successfully.
Prof Stebbing has faced more than 100 days of legal hearings since January 2020. Covid, holidays and illness have caused delays and the MPTS has admitted that the case was “beset with difficulties from the outset”.
Earlier this year the service said: “It is imperative that progress is made in this case.”
A Freedom of Information request has uncovered that hearing costs alone have already topped £300,000, with the tribunal still scheduled to continue until November 12. That does not include the investigative and legal costs for Prof Stebbing.
During this week’s hearing, the GMC’s counsel argued that Prof Sikora’s claim that the 12 patient cases had been cherry-picked over others was invalid because the number of examples was unknown.
Prof Stebbing’s barrister, Mary O’Rourke QC, suggested that was because the GMC had refused to consider those instances, including 600 other compiled patient cases, being submitted.
The hearing continues.