The principle of liability of a master for the torts committed by his servant is known as vicarious liability. Vicarious liability is a legal doctrine where one person is held responsible for the wrongful acts of another, even though the first person did not directly commit the act. In the context of master-servant relationships, this doctrine is encapsulated by the maxim 'respondeat superior' (let the master answer) or 'qui facit per alium facit per se' (he who acts through another acts himself).

Rationale for Vicarious Liability: Several justifications underpin this principle:

1. Deep Pocket Theory: The master usually has greater financial resources to compensate the victim than the servant.
2. Control and Benefit: The master has control over the servant's actions and benefits from the servant's work, so it is fair that they bear the risks associated with that work.
3. Deterrence: Holding masters liable encourages them to ensure their servants are properly trained and supervised, thereby preventing future torts.
4. Loss Distribution: It allows the cost of accidents to be spread across the community through insurance.

Conditions for Master's Liability: For a master to be held vicariously liable for the torts of their servant, two primary conditions must be met:

1. The wrongdoer must be a 'servant': The relationship between the master and the wrongdoer must be that of employer and employee (master and servant), not an independent contractor. The key distinction lies in the degree of control the employer exercises over the manner in which the work is done. A master controls not only what is to be done but also how it is to be done, whereas an independent contractor is typically only told what to do, not how to do it.

2. The tort must be committed 'in the course of employment': This is the most crucial and often litigated aspect. An act is considered to be in the course of employment if it is:

   • An authorized act: An act that the master expressly or impliedly authorized.
   • An unauthorized mode of doing an authorized act: Even if the servant performs an authorized act in an improper, negligent, or even prohibited manner, the master can still be liable. For example, in Century Insurance Co Ltd v Northern Ireland Road Transport Board (1942), a tanker driver negligently lit a cigarette while transferring petrol, causing an explosion. The employer was held liable because lighting a cigarette, though unauthorized, was an unauthorized way of performing an authorized task (transferring petrol).
   • Incidental to the employment: Acts that are reasonably incidental to the performance of the servant's duties.
   • Acts done for the master's benefit: Even if the act is not strictly authorized, if it is done with the intention of benefiting the master, liability may arise.

Distinction: 'Frolic of his own': If a servant acts entirely outside the scope of their employment, on a 'frolic of his own', the master will not be liable. This means the servant has completely departed from their duties and is pursuing their own interests. For example, if a delivery driver deviates significantly from their route to visit a friend, the employer would likely not be liable for an accident during that deviation.

Case Laws:

• Lister v Hesley Hall Ltd (2001): This House of Lords case significantly broadened the 'course of employment' test, particularly in cases of intentional torts like sexual abuse. It held that if there is a 'sufficiently close connection' between the employee's tortious act and the employment, the employer can be vicariously liable, even if the act was not authorized or was a criminal act.
• State Bank of India v Smt. Shyama Devi (1978): The Indian Supreme Court held that a bank is not vicariously liable for the fraud committed by its employee if the employee acts in his private capacity and not in the course of his employment. In this case, a bank employee fraudulently induced a customer to deposit money with him personally, not with the bank. The court distinguished between acts done within the scope of employment and acts done by the employee in his personal capacity.
• Pushpabai Purshottam Udeshi v Ranjit Ginning & Pressing Co. (1977): The Supreme Court reiterated that for vicarious liability to arise, the servant's act must be within the scope of his employment, or an unauthorized mode of doing an authorized act. If the servant acts for his own benefit, the master is not liable.

In summary, vicarious liability holds the master responsible for the torts of their servant, provided the servant was acting within the course of their employment, reflecting a policy choice to ensure victims are compensated and to encourage responsible management.