Scottish prisoners were asked to donate blood for transfusions until 1984, despite concerns that the practice was unsafe, it has emerged.
The practice was stopped as scientific evidence developed
The practice has come to light because of new laws on the freedom of information.
Minutes from meetings of senior blood service managers show donations were still being taken in 1983.
Prisoners are known to have a higher incidence of HIV and Hepatitis C because of drug-taking.
The minutes were taken at meetings of Scottish Blood Transfusion Service managers in the early 80s.
Campaigners said they were shocked that blood from such a high-risk group was still being collected at a time when the risks from tainted blood were beginning to emerge.
In recent years, hundreds of people in Scotland have died from Aids and Hepitatitis C after being given infected blood and blood products.
The Blood Transfusion Service said that it changed the rules on who could donate blood as scientific evidence became available.
From January 2005 the Freedom of Information (FOI) Act 2000 gives a general right of access to all types of recorded information held by public authorities.