Breast cancer sufferers may have suffered significant delays in diagnosis after an investigation found the Royal Free struggled to cope with a tide of new referrals.

A report into care given by the hospital, prompted by a whistleblower doctor, said a “number of improvements” had needed to be made to its breast unit, including the recruitment of more staff and running of additional clinics.

It comes after the whistleblower contacted the Ham&High back in March to claim that “grossly inadequate resources” were causing considerable delays in diagnosis; that cancer sufferers were facing “disgraceful” five-hour waits when they arrived for their appointment; and that excessive workloads meant staff were forced to work without any break.

The doctor, practicing at the hospital in Hampstead as a locum, said things had got so bad at the unit, abuse from patients angry with the service had caused low morale among staff. A breakdown in communication even saw him witness staff “shouting and screaming at each other” in the department.

The Royal Free promptly launched an investigation into the doctor’s claims. The resulting report, authored by Professor George Hamilton, described the whistleblower’s revelations as “invaluable” and found the unit had been under strain following a rise in referrals in recent years.

On top of hiring more staff, the Royal Free has since made moves to solve overcrowding of the service. This was after the whistleblower reported patients were forced to stand for hours without access to water or toilets while waiting.

The whistleblower had also suggested “senior and distinguished” consultants were forced to suffer “interfering” hospital managers who would involve themselves in clinical decisions, including dictating to surgeons whether they could carry out procedures unaided or not. Prof Hamilton, a vascular surgeon, neither confirmed nor denied the allegation, but agreed that managers “have no clinical experience and therefore it is not in their remit to advise [on this]”.

He also agreed it was “unacceptable” consultants were so overworked they were reportedly eating their lunches while assessing women for cancer.

The trust had originally told the Ham&High that one allegation, that a fatigued doctor had made surgical errors, was not true.

While Prof Hamilton’s report noted the operation, which involved the removal of a tumour, had been successful, it also admitted the trust had to speak with the surgeon after the procedure left the patient with a scar in a “sub-optimal position”.

A spokesman for the Royal Free said: “The report acknowledges that an increase in the number of patients being referred put some strain on the unit. A number of improvements have since been made to the service.”