A surgeon who had his manslaughter conviction quashed says "justice has not been done" for the patient's family.
David Sellu, 69, served 15 months of a two-and-a-half-year prison term for manslaughter by gross negligence.
James Hughes, 66, was under Mr Sellu's care when he died at the Clementine Churchill Hospital in Harrow in 2010.
On Tuesday, the Court of Appeal ruled the November 2013 conviction was not safe.
The appeal judges said the trial judge did not give the jury adequate legal guidance on what gross negligence meant.
'Justice not done'
Speaking after the conviction was quashed, Mr Sellu said there was a range of factors which contributed to Mr Hughes's death, including problems with the whole system at the hospital.
"I think for the sake of that poor man and his family justice has not really been done," he said.
"It has been retribution, but I don't really believe that they've been served as well as they should have been."
Mr Hughes became ill after a routine knee replacement carried out by another surgeon.
Mr Sellu later carried out surgery to repair a perforated bowel, but there had been delays in that carrying operation. Mr Hughes died two days later.
The original case against Mr Sellu, of Hillingdon, was based on the standard of his care over about 25 hours.
Mr Sellu argued he knew Mr Hughes needed an urgent operation, but an anaesthetist was not available for several hours and it was not safe to move the patient to the nearby hospital.
"It really was another routine day. A busy day of course, but I'd been used to working in this sort of way for many, many years," Mr Sellu said.
Mr Sellu's medical licence was suspended when he was convicted and would only be reinstated after a General Medical Council (GMC) hearing.
The Crown Prosecution Service has decided not to seek a retrial.
In a statement, Mr Hughes' family said the doctor had "served his sentence".
"Our father's suffering was not prioritised as the emergency it so clearly was," they said.
A spokesman for Clementine Churchill Hospital said the "original prosecution was a criminal case led by the Crown Prosecution Service and the police".
"Our thoughts remain with the family of Mr Hughes," he said.