S stabbed B in a fight about B stealing his carpentry tools and killed him. He had a medical condition that made him react angrily to small provocations. The judge applied the Diplock test, saying that the medical condition was relevant to deciding how serious the provocation was to him, but that it did not excuse him from exercising the self control of a reasonable man. His appeal was allowed by CA who said that his medical condition was to be applied and no distinction was to be drawn between its effect on the seriousness of the provocation and its effect on his reaction to the provocation. Quality judgement- supports Steyn’s objections in case above. Hoffman says that though there is theoretical justification in Diplock’s distinction (if a person claims to lack self control then they are in a mental state of diminished responsibility), in practice mental abnormality does not apply to just one part of the character (judgement of provocation and not self control) and that this has been an impossible distinction to follow.