Why Is The Pinochet Not Regarded As An Official Act?

Martin Dixon and Robert McCoruodale in their book when disusing the Pinochet case observe that in the UK, the immunity of a head of state can only be valid and recognised only if the acts in question were done in an official capacity and that if the acts are related to the state. This has it that there is a relationship between acts done in an official capacity by heads of state and the state itself. They say that there is a question that arises in the Pinochet case as to whether torture was not regarded in the case to be an official act because torture as an act cannot be regarded as official under international law or because torture is a crime under international law thus immunity being exempted. They seem thus to be justifying the acts done by heads of state that can lead to them being prosecuted or not.
These are changes according to him that have changed the way the doctrine of immunity for heads of state was viewed in the past and how it’s being viewed currently. He calls these changes as being dramatic because they have brought about unsettled issues and conflicts in its applicability. He is of the opinion that a head of state does not have to be held accountable for the acts done while in office because it is presumed that those acts are linked to the state and therefore considered as the acts of the state. His views that a head of state does not have to be held accountable for official acts seems to be contradictory with how the doctrine of immunity for heads of state is viewed presently as there a head of state is regarded to be individually criminally responsible for crimes committed during or after leaving