Assignment generally means the transferring of an interest or benefit from one person to another.

In contract law, where A and B have made an agreement, A can transfer the benefit of that agreement to C, but not the burden. A remains contractually bound to perform their obligations to B, but any benefit accrues to C.

Assignments can be legal or equitable (for example if formalities, such as a requirement to notify in writing, are absent).

For A to transfer both the burden and the benefit to C, novation is required.

Novation is essentially a replacement of the original contract between A and B with a new one between C and B, under which C takes both the benefit and the burden of the agreement with B. When people talk of the “assignment” of a contract or lease, they usually mean novation.

The distinction between assignment and novation is more fully explained in a recent case involving construction contracts, Energy Works (Hull) Ltd v MW High Tech Projects Uk Ltd  [2022] EWHC 3275 (TCC), in which Pepperall J cites the classic dicta of Lord Browne-Wilkinson in Linden Gardens Trust Ltd v Lenesta Sludge Disposals Ltd [1994] 1 AC 85, at 103:

“It is trite law that it is, in any event, impossible to assign “the contract” as a whole, i.e. including both burden and benefit. The burden of a contract can never be assigned without the consent of the other party to the contract in which event such consent will give rise to a novation. … Although it is true that the phrase “assign this contract” is not strictly accurate, lawyers frequently use those words inaccurately to describe an assignment of the benefit of a contract since every lawyer knows that the burden of a contract cannot be assigned…”