Bereaved families who lost loved ones in the contaminated blood scandal say they have seen evidence that proves their relatives were being "used for research" without their knowledge and despite clinicians knowing the risks.

Historical notes in medical records found by campaigners are said to show that some patients being treated for the blood clotting disorder haemophilia in the 1970s and 1980s were given blood plasma treatment which doctors knew might be contaminated and infect them with hepatitis. Clinicians involved in the treatment have maintained they wanted to study the links between the haemophilia treatment Factor VIII and the risk of infection.

Jason Evans, director of the campaign group Factor 8, believes that instead of stopping treatment, clinicians lobbied to continue trials, even after identifying the association between hepatitis and the treatment. He has found notes alluding to the research in his own father's medical records.

Read more:Infected blood compensation scheme 'to be extended'Campaigners concerned govt may seek to delay paying compensation Mr Evans, whose father died in 1993 after being infected with both HIV and hepatitis C during the course of his treatment for haemophilia, said: "It is appalling that hundreds of people with haemophilia across the country were knowingly infected with lethal viruses under the guise of scientific research. "These secret experiments, conducted without consent, show individuals were treated as mere test subjects, not human beings.

"The fact that this could happen on such a scale, over such a long period of time, is almost incomprehensible." Documents - obtained through Freedom of Information requests and medical records provided by families - reveal a timeline of the trials, led by a senior medic who worked for the now defunct Public Health Laboratory Service, say campaigners. Becka Pagliaro from Waterlooville, near Portsmouth, said she was "shocked" to find notes about the trials in her father's patient notes.

Her father Neil King was co-infected with both HIV and hepatitis C while receiving treatment for haemophilia. He died in 1996 when he was 38 years old.

"When I got his medical records I saw he was part of this research which I know was something that he would not have agreed to, so that was done covertly," Ms Pagliaro said. "I was really shocked - I wondered first of all whether I had received someone else's medical records because I could not believe what I was seeing." Janine Jones' brother Mark Payton died when he was 41 after being co-infected with both hepatitis C and HIV.

"When I saw the research was on my brother's records I thought: 'What's this?' And after asking a few questions I didn't get anywhere," said the 59-year-old from Warwickshire. "It was only the last few months that it really came to light - they were being used for research." Emma Frame, from South Shields, said that her father had never agreed to be part of studies but found multiple references to them in his medical records.

Ms Frame said: "I have all of his records which is where I came across these studies. "There is no information other than this doctor's name, a treatment and then a date.

With my dad it was recorded several different times. "It's absolutely mind-blowing the information that is out there that has been hidden." Jeffrey Frame was co-infected with HIV and hepatitis C and died in 1991 when he was just 39.

Ms Frame said that in the mid 1990s she also discovered that the NHS had kept some of her father's "samples.