It is in fact the role of a pharmacist to reduce medication errors - and this is achieved through a series of checks - largely focussed on asking 'is this the right medicine and dosage for this patient and the condition to be treated?' and 'has the correct medicine, dosage and dosage form been dispensed?'
Errors tended to occur outside of pharmacy's area of control; in theatres to where pharmacists often have little access, in ward settings where medicines are administered in sometimes noisy and chaotic environments, in clinical teams where pharmacists are not allowed to have a presence, and indeed in the modern NHS where pharmacy staffing levels are severely reduced.
A technological solution is possible - based on the concept of checklistbundles, patient medical and medication record systems and image scanning technology - but it is usually hard to sell clinicians on the idea of a check-list never mind anything else.
Until there is a true incentive to change practices around medication administration (i.e. unlimited fines) this will always be a hard thing to change.