A human brain left in the wrong corpse was among hundreds of serious incidents in mortuaries over a three-year period.
An undertaker found the brain in the abdominal cavity of a different body at Warwick Hospital.
The alarming error was corrected immediately, according to a BBC Freedom of Information request to the Human Tissue Authority.
In total, there were 278 serious incidents in England, Wales, and Northern Ireland from 2014 to 2016.
The FOI request found the wrong body was released to families 36 times, while organs were found by hospitals after the body was released on 13 occasions.
The data covers post-mortems, which are when a dead person’s organs are removed from their body for examination.
A pathologist will usually return the organs to the body after the post-mortem has finished.
A serious incident, according to the HTA, is something involving ‘human errors or system failures’ that lead to damaged or misplaced bodies and body parts.
Although errors do happen, the HTA said they are rare and ‘should never happen’.
At King’s College Hospital in London, changes were made after a large corpse couldn’t be removed because of how it was frozen.
South Tyneside NHS Foundation Trust apologised to a family when it was revealed they had been storing a father’s brain 22 years after his death.