Contracts do not stand in isolation but rather exist within specific contexts, especially when it comes to business and commerce.

Firstly terms can be implied by customs that exist within certain sectors (Hutton v Warren (1836)).

It is important to note however that customs cannot override the express terms of a contract (Les Affréteurs Réunis Société Anonyme v Leopold Walford Ltd [1919]). This is also expressed through the Latin phrase Expressum facit cessare tacitum.

Terms can also be implied by statutes such as through the Sale of Goods Acts and more recently the Consumer Rights Act 2015. This is often necessary to protect the party that is in in the weaker bargaining position.

Finally the courts may imply terms into a contract but again these should not be inconsistent with the express terms (Lynch v Thorne [1956]).

There are many areas in which the courts have implied terms in order to meet what might be considered reasonable expectations:
* employment; Lister v Romford Ice & Cold Storage Co Ltd [1957]
* landlord & tenant; Liverpool City Council v Irwin [1977]

The courts may also imply terms in order to remedy a failure of expression. As Bowen LJ noted in The Moorcock (1889):
“the implication is to give such business efficacy to the transaction as must have been intended”.

There is also an open question about what should happen when the term appears obvious but might not have been agreed to by one of the parties (AG of Belize v Belize Telecom Ltd [2009]).

It should be noted that a contract can expressly exclude implied terms although this should be clear (Johnstone v Bloomsbury Health Authority [1991]).