When someone gets in touch with a solicitor with a case that ends up making it to court, they are not only fulfilling a legal and administrative duty but also contributing to a wider set of legal precedents that could have ramifications far into the future.

There are many cases that form a legal butterfly effect, where their relatively small stakes ultimately lead to much larger determinations and given that case law is at the bedrock of how the law functions in our everyday lives, it often affects how people live.

Here are just a few examples of cases that ultimately had a huge impact on the legal world.

A Quack’s Marketing Campaign Establishes Unilateral Contracts

The foundations of contract law, particularly when it pertains to buying products and unilateral contracts, were established by a ball filled with phenol vapours that claimed to cure the flu.

The case of Carlill v Carbolic Smoke Ball Co involves a company that sold a product that claimed to cure and prevent the flu, with advertising displaying a reward of £100 (over £10,000 today) if someone contracts the flu after using the ball.

Louisa Carlill used the smoke ball three times a day, but it was only two months because she contracted influenza. However, when she tried to claim the reward, the company evaded her requests. She ultimately took them to court.

Interestingly, in a case so vivid and fascinating that it is often the first contract law case studied by law students, it was ruled that the advert in question constituted a unilateral contract or a contract where one party would pay the other only after a task was completed.

The advertisement was said to contain the four elements of a contract (an agreement, a monetary consideration, an intention to create a binding contract and certainty to the terms of the agreement).

The intention was found by the justices presiding due to the statement in the advert that £1000 was in a bank to prove their sincerity, despite later claims of mere puffery (exaggeration in advertising).

Amusingly, the Carbolic Smoke Ball Company failed to learn their lesson and actually increased the award for the use of the smoke ball, albeit with more restrictive conditions, before it was wound up just three years later in 1896.

A Scottish Snail Establishes The Duty Of Care

Negligence when it comes to products and services is based on the concept of the duty of care or the legal obligation that manufacturers have to ensure that customers are not hurt by consuming in the course of using their products or services.

Interestingly, this fundamental principle, seen throughout the legal world and one that in large and small ways affects every single person in Great Britain and Northern Ireland, began with a snail soaked in ginger beer.

Mrs May Donoghue wanted a Scotsman ice cream float, which involved a mixture of ice cream and ginger beer, but once she poured the soft drink over the ice cream after trying a little bit of the mixture, a dead snail fell out.

She very quickly fell ill, checked herself into hospital and was diagnosed with gastroenteritis.

What complicated the case was that Mrs Donoghue had not bought the drink, and the legal precedent at the time was that a manufacturer only had a duty of care to a customer with which they had a contractual relationship.

This extended liability to the ultimate consumers of a product, meaning that, in this case, David Stevenson of Scotland had a duty of care not only to the cafe owner to whom he sold the ginger beer but also to the person who paid him for the Scotsman ice cream float and ultimately the lady who drank it.