Thanks for dropping by. Quantum meruit is one of the historical common counts of indebitatus assumpsit. The others are money had and received, money paid to the defendant for the use of the plaintiff, and quantum valebant. They were money claims at common law, not equity. Formerly described as arising quasi ex contractu, or in quasi-contract, they are now understood as claims to restitution of unjust enrichment. In particular, the quantum meruit was a claim for the reasonable value of work done. If there is no contract for that work (either because none was agreed, or was uncertain, or was void), then, as Goff J put it in BSC v Cleveland Bridge Co [1984] 1 All ER 504 “the law simply imposes an obligation on the party who made the request to pay a reasonable sum for such work as has been done pursuant to that request, such an obligation sounding in quasi-contract or, as we now say, in restitution”.