Like the interpretation of the express words in a contract, the implication of terms in fact is traditionally explained as a way of the court giving effect to what the parties intended, judged objectively. So the two processes have something in common at a high level of generality. Much more controversial is the suggestion, made by Lord Hoffmann giving the opinion of the Privy Council in Attorney General of Belize v Belize Telecom Ltd  1 WLR 1988, that the process of implying terms is merely an aspect of interpretation: ‘There is only one question: is that what the instrument, read as a whole against the relevant background, would reasonably be understood to mean?’ This analysis, which generated intense academic debate, had not been considered by the Supreme Court until the recent decision in Marks and Spencer plc v BNP Paribas Securities Services Trust Company (Jersey) Ltd  UKSC 72.
Janet O’Sullivan, Silence Is Golden: Implied Terms In The Supreme Court. Cambridge Law Journal / Volume 75 / Issue 02 / July 2016, pp 199-202.