[28] The fifth relevant principle is that terms may be implied in one of four ways. The trial judge set out this orthodox classification in his unreported interlocutory judgment in Carlton & United Breweries Ltd v Tooth & Co Ltd (Hodgson J, 11 June 1985, unreported) but summarised at (1985) 6 IPR 319, which was quoted by Young J, the trial judge in that case (Carlton & United Breweries Ltd v Tooth & Co Ltd (1986) 7 IPR 581 at 605-606):
"A more precise classification of the different types of implied terms was given by Hodgson J in his first interlocutory judgment in the current proceedings. His Honour set out four classes of implied terms, the first two of which are in the class of terms implied in law, the second two the implied terms in fact. His Honour said:
'There is a spectrum of different types of implied terms covering, inter alia, the following:
(i) Implications contained in the express words of the contract: see Marcus Clarke (Vic) Ltd v Brown [1928] HCA 12; (1928) 40 CLR 540 at 553-4.
(ii) Implications from the "nature of the contract itself " as expressed in the words of the contract: see Liverpool City Council v Irwin [1976] UKHL 1; [1977] AC 239.
(iii) Implications from usage (for example, mercantile contracts).
(iv) Implications from considerations of business efficacy: see BP Refinery (Westernport) Pty Ltd v Hastings Shire Council [1977] HCA 40; (1977) 52 ALJR 20 at 26; Codelfa Construction Pty Ltd v State Rail Authority of NSW [1982] HCA 24; (1982) 149 CLR 337.' "
[29] The reasoning of the trial judge conformed to these principles. The submissions of the defendant did not.
(a) Implication of terms to give business efficacy
[30] The criticism based on failure to apply the principles as to the implication of terms fastened on the fact that the trial judge described what he did as a "drawing out of what is implied by the language of the contract itself ". The defendant cited the leading cases about implying terms to give business efficacy and developed arguments designed to show that the terms found by the trial judge were not reasonable, equitable, necessary or obvious. This criticism is entirely baseless. The trial judge made it plain that he was not implying a term to give business efficacy. He said: "This is not an implication of a term by operation of law or on the basis of business efficacy; but rather the drawing out of what is implied by the language of the contract itself ".
[31] The trial judge was indicating that, of the four implications he had referred to in Carlton & United Breweries Ltd v Tooth & Co Ltd (1985), he was not making implication (ii) or (iv), but (i). Despite the number of occasions on which the defendant said that what the trial judge "was really doing was implying a term and on a basis that didn't comply with the usual rules", the processes he employed were processes of construction.[76]