There are legal processes that define how a tenancy can be brought to an end. This guidance explains what they are. It is prescriptive but only when it needs to because of what the law says.
 
Sometimes it is clear that prompt action is needed to bring a tenancy to an end (if a property has been abandoned for example).  On other occasions it is a matter of judgement - taking into account that formal enforcement action often isn’t the best way to resolve an issue.
 
This guidance doesn’t cover making those judgements even though they are often not easy. It sets out the steps that are necessary once a decision has been made to take steps to end a tenancy.  If in doubt about whether to take possession action talk it over within your team or with your manager.