Lucy Connolly had taken toddler Harry to an out-of-hours GP service in Northampton on April 29, 2011 as he was suffering from severe diarrhoea and vomiting.
The little boy had already been admitted to Northampton General Hospital twice in the preceding six days. He was seen at the out-of-hours service by Dr Aboo Thamby, who decided he did not need to be admitted to hospital despite being, according to his mum, lifeless and unresponsive.
Instead, Dr Thamby advised Harry's parents to get him to eat some rice and yogurt.
Two days later, the little boy's dad, Ray, found him dead in his bed. A post mortem revealed he died of dehydration and acute kidney failure after suffering from an inflammation of the colon.
Mrs Connolly and her husband subsequently reported Dr Thamby to the GMC, who concluded that he 'failed to put himself in a position to make an adequate diagnosis by either examining the patient or by eliciting and acting upon an appropriate history'.
The GMC ruled that his 'inaction meant that an opportunity to save the child was lost'.
At the inquest into Harry's death last year, a narrative verdict was recorded by county coroner Anne Pember who catalogued a series of 'failures' and 'catastrophic' errors made by the doctors and nurses who treated the little boy.
Harry's mum says she is outraged by the GMC's decision to allow Dr Thamby to continue to work as a GP.
"I think it is disgraceful. I don't see how giving him a warning makes any difference," she told her local paper.
"He gave me the wrong medical advice and did not examine Harry properly. Since the day Harry died he has been allowed to continue working as a GP. He has never apologised to us."
The heartbroken mum also added that 'nobody seems to be held accountable for the 'catastrophic errors which were highlighted by the coroner'.
The GMC ruling against Dr Thamby also made reference to another patient who he 'failed to take an adequate history or arrange for an examination' of.
A spokesman for the Northamptonshire out-of-hours service said Dr Thamby no longer worked any shifts there, but Kingsthorpe Medical Centre, said Dr Thamby was still practising there and would 'continue to do so'.