Legal concepts, side by side

Murder is the unlawful killing of a person with intent to kill or cause grievous bodily harm; manslaughter is an unlawful killing without that intent, or a murder reduced by a partial defence. The key differences are the mental element (mens rea) and the sentence.

Robbery is theft committed with the use or threat of force (s 8 Theft Act 1968); burglary is entering a building as a trespasser with intent to steal, inflict grievous bodily harm or cause criminal damage — or committing theft/GBH having entered as a trespasser (s 9). Robbery turns on force; burglary on trespassory entry.

A lease grants exclusive possession of land for a term and is a proprietary interest that can bind third parties; a licence is mere permission to be on land — it is personal and does not confer exclusive possession.

A void contract has no legal effect from the outset — in law it never existed — whereas a voidable contract is valid and binding unless and until the innocent party chooses to set it aside (rescind it).

An offer is a clear statement of terms the offeror is prepared to be bound by the moment it is accepted; an invitation to treat is merely an invitation for others to make offers. The distinction decides who is the offeror and when a binding contract forms.

A condition is a major term of a contract that goes to its root: its breach lets the innocent party terminate the contract and claim damages. A warranty is a minor term: its breach gives a right to damages only, not termination.

Common law is the body of law developed by the old courts of law, giving remedies as of right (chiefly damages); equity is the body of principles developed by the Court of Chancery to soften the rigidity of the common law, giving discretionary remedies such as injunctions and specific performance.

Negligence protects against careless conduct causing foreseeable harm to a person or property and requires a breach of a duty of care; private nuisance protects the use and enjoyment of land against unreasonable interference and does not require proof of carelessness.