20 In both these cases (as in a great number of others that could be mentioned), the parties expressly recognised that, despite the retention of title clause, the buyer might in fact on-sell the relevant goods and thereby generate proceeds. Having acknowledged that, the parties made specific provision under which the seller was to have an interest in the proceeds, with that interest taking the place, as it were, of the originally reserved interest in the goods themselves. If, in those cases, the parties took care to adopt the express term regarding isolation and retention of the proceeds of sale, how can it be, one asks rhetorically, that such a provision is so obvious that it goes without saying?
21 In the present case, the contract, construed in the light of the course of trade indicated by the other documents I have mentioned, appears to recognise that AQP is an on-seller of oranges ordered from Toveill, being oranges delivered or consigned by Toveill but not yet paid for by AQP. One possible characterisation of the nature and consequences of the transactions is therefore that stated by Roskill LJ in Aluminium Industrie Vaassen BV v Romalpa Aluminium Ltd [1976] 1 WLR 676 at 690 (in the following passage, "the defendants" correspond with AQP and "the plaintiffs" with Toveill):
"I see no difficulty in the contractual concept that, as between the defendants and their sub-purchasers, the defendants sold as principals, but that, as between themselves and the plaintiffs, those goods which they were selling as principals within their implied authority from the plaintiffs were the plaintiffs' goods which they were selling as agents for the plaintiffs to whom they remained fully accountable. If an agent lawfully sells his principal's goods, he stands in a fiduciary relationship to his principal and remains accountable to his principal for those goods and their proceeds. A bailee is in like position in relation to his bailor's goods. What, then, is there here to relieve the defendants from their obligation to account to the plaintiffs for those goods of the plaintiffs which they lawfully sell to sub-purchasers? The fact that they so sold them as principals does not, as I think, affect their relationship with the plaintiffs; nor, as at present advised, do I think - contrary to argument of counsel for the defendants - that the sub-purchasers could on this analysis have sued the plaintiffs on the sub-contracts as undisclosed principals for, say, breach of warranty of quality ."
22 In the Romalpa case, however, the contract for sale contained not only a retention of title clause with respect to the goods sold but also an elaborate provision about the consequences of mixing of those goods with others in a manufacturing process, the general thrust of which was that the seller of the original goods was to have ownership of the new product until payment. The fact that the parties had adopted that provision played a part in the Court of Appeal's decision on a question not directly addressed by the contract, namely, the right of the seller to trace and recover proceeds of on-sales made by the buyer before payment of the price. But the principle stated by Roskill LJ in the quoted passage does not obviously depend on the existence of any contractual provision regarding the proceeds. It turns rather on the existence of authority of the buyer to sell the goods to which it has no title, which authority is seen to be a product of agency. And once agency is recognised, the possibility that the agent may owe fiduciary duties to the principal arises and indicates the potential availability of equitable remedies.