Enlisting close connections: a matter of course for vicarious liability?

In determining whether an employer is vicariously liable for the torts committed by his employee, the House of Lords in the landmark decision of Lister v Hesley Hall proposed that courts should now focus on the relative closeness between the nature of the employment and the tort. Unfortunately, this touchstone test simply begs the question of how close must the nature of employment and the tortious action be before liability can be found. To say that the tort in question was inextricably interwoven or so closely connected with the nature of the employment is conclusory not prescriptive. The close connection test in itself merely provides the court with a formula to confirm its result, not reach one. This author seeks to argue instead that the following legal tests should be employed to determine whether an employee's wrong was committed in the course of his employment. (1) Where the employee has been negligent in the performance of his duties or where the employee has deliberately engaged in self-serving conduct (not amounting to a tort) and in doing so negligently causes injury to another, the employer would only be vicariously responsible if the injury suffered by the victim arises from the inherent risks of the employment. (2) Where the tort committed by the employee is trespassory/intentional in nature, the employer would only be vicariously liable if he has materially increased the likelihood of occurrence of an injury that arises from an inherent risk of the employment. Essentially, my suggested formula would only find liability when the injury suffered by the victim arises from the risks inherent in the tortfeasor's employment, ie the employer would not be liable for all risks he creates when the wayward worker is in his employ.