1. Masters (employers) are held vicariously liable for torts committed by their servants (employees) in the course of their employment. That is so even if the tort committed is one which they have not ordered or authorized.

2. Employers who are liable may sue their employees (rare):
Lister v. Romford Ice and Cold Storage Ltd. 1957 - son injuring his father while parking a lorry, the company had to pay but then successfully sued the son.

3. Servants
a) A servant is any person who works for another upon the terms that he is to be subject to the control of that other in respect of the manner in which he shall do his work. Skilled self-employed workers and independent contractors are not servants for the manner in which they do their work is not subject to the control of the other party in a con- tract for services. However, they may be servants of someone else who is then vicariously liable.
Business integration test: Stevenson, Jordan and Harrison v. McDonald 1952 - does the employer have the right to tell the employee what to do and how to do it? Further question (Denning): is the employee fully integrated or only an accessory?
b) But this definition is subject to modifications: hospital authorities have been held vicariously liable for the negligence of nurses, radiographers and even whole-time assistance medical officers; companies are liable for the misdeeds or their executives.
Even when third parties are involved, an employer may be vicariously liable for their acts:
Rose v. Plenty 1976 - children helping the milkman, company had the benefit.
c) Self-employment or not?
Ready Mix Concrete v. Minister of Pensions 1968 - concrete delivery company created 'owner-drivers' but maintained a high degree of control - drivers owned the tools and paid the rates, so the company was not liable.
Market Investigations v. Minister of Social Security 1969 - interviewer with flexible hours and no sick pay, no holiday, and the right to work for third parties was considered an employee!
Massey v. Crown Life Insurance 1978 - a self-employed (save taxes) was sacked - he had to stick with it.
Young and Woods v. West 1980 - a worker was 'self-employed' in order to save taxes, but this was not accepted by the court; he lost, of course, the tax advantage.
Ormrod v. Crossville Motor Service 1953 - car to be transported to Monte Carlo; principal was liable.
d) Husband-wife:
Morgans v. Launchbury 1973 - husband taking wife's car on a drunk-drive; he was not her agent.
For the present purposes the servant is a person for whose torts another will at any given time, in accordance with current policy, be held legally responsible.

4. The course of employment
a) Breach of duty?
aa) A mere 'deviation' from the duty (i.e. a lorry driver taking a detour) will still be held 'in the course of employment':
Century Insurance v. Northern Ireland Road Transport Board 1942 - lorry driver smoking a cigarette and causing an explosion.
Bayley v. Manchester, Sheffield and Lincolnshire Railway 1873 - porter pulling a man off what he thought was the wrong train.
Poland v. John Parr and Sons 1927 - employee seeking to prevent theft during lunch break, being under no duty to do so: employer was liable - employee had acted reasonably.
Whatman v. Pearson 1868 - an employee was not to go home for lunch, nevertheless did so taking the employer's horse, which broke free and caused an accident. He had not taken as different route as he would have taken in carrying out the business.
Lloyd v. Grace, Smith and Co. 1912 - solicitors' clerk misappropiating client's money and inducing him to transfer property to him.
Williams v. Hemptill 1966 - bus driver taking detour because the kids on the bus told him so.
bb) But a 'departure' from the duty (i.e. a lorry driver taking the opposite direction) will not - this will be 'a frolic of his own':
Storey v. Ashton 1869 - lorry driver, though only 'detouring', carried out his own business.
Heasemans v. Clarity Cleaning 1987 - cleaning woman making expensive telephone calls.
Irving v. The Post Office 1987 - postman writing discriminating stuff on a letter.
Warren v. Menly's Garage 1948 - attendant hitting a customer whom he thought not to have paid.
b) An employers may be liable even if he has prohibited the servant from doing the act in question. Such a fact, though relevant for the question whether or not an act was in the course of employment, cannot of itself exculpate the master.
No employer can excape liability just by prohibiting his servants to 'commit any torts' during their service: Limpus v. London General Omnibus Co. 1862 - driver racing against the competition against express orders.
c) Where an employer ('general employer') hires out an employee to another, 'special employer' for some particular pur- pose or for a period of time, liability depends on the fact who had the right to control over the servant's activities at the relevant time:
Mersey Docks and Harbour Board v. Coggins & Griffiths (Liverpool) Ltd. 1947 - the general employers were responsible although the contract with the special employer transferred control to the latter. The general employers bears the onus of establishing that responsiblity has been shifted.
d) As a rule, no one is responsible for the torts committed by independent contractors. Exceptions:
aa) Where the contract, if properly implemented, is likely to involve the commission of a tort.
bb) Whre an especially high duty of care is imposed upon a person by law, such a the duty to secure a building:
Tarry v. Ashton 1876 - repairs at a house injuring a passerby.
cc) Where liability is strict (Rylands v. Fletcher 1868).