Julius Quilter was head of the "BEAGLE" project, which researched human evolution. The project involved cultivating specimens of what the human race might evolve into. Three creatures were created. Two of them died while the third thrived initially, but grew weak later.
Near death, the creature, named "Alfred", transplanted organs from one his guards into his own body, prolonging his life. The resultant horror resulted in the project closing in 1975. Unable to kill the creature, Quilter had instead secretly reared the beast and educated it, eventually making him his assistant and giving him the name "Alfred Emerson".
Quilter seemed to ultimately be under the control of the creature, convulsing in pain at times apparently due to the presence of Emerson. Liz Shaw's P.R.O.B.E. began to investigate the "BEAGLE" project after a series of deaths involving missing organs - much like the death of the guard in 1975. After Quilter's death under questioning, Brian Rutherford called at Quilter's home to pay his respects. There, Emerson held Rutherford captive while he revived Quilter's body, perhaps intending to harvest Rutherford's organs to help the process. Only the intervention of Liz and Col. Ackroyd saved Rutherford and killed Emerson. (TV: Unnatural Selection)