Dr Arthur Codd stated that it was known that viruses were transmitted in this way: "we knew there was always a risk there might be other things lurking there" adding that it had always been his advice to create a "pedigree herd" of volunteer donors in order to minimise the risk of infection. A decision was made to import commercial concentrates stating that "We could not have met demand at that time but we could have continued with the older products until Britain became self-sufficient."