Secret reports on patient harm in NHS care
26 November 2012 Last updated at 15:25 GMT
BBC Scotland has obtained more than 300 reports from inside the NHS which have been kept secret up until now.
They detail serious incidents, over the past year, where patients have come to harm during their care.
Former NHS staff are accusing their health board of covering up mistakes rather than learning from them.
BBC Scotland's Fiona Walker reports.
Watch BBC Scotland Investigates: How safe is your hospital? at 22:35 GMT on BBC One Scotland on Monday 26 November.
The programme will be available to watch for seven days following transmission on the BBC iPlayer.