Lord Mance said,

12 In my opinion, the conclusion reached below attaches too much weight to what the courts perceived as the natural meaning of the words of the third sentence of [the clause], and too little weight to the context in which that sentence appears and to the scheme of the security trust deed as a whole. Lord Neuberger was right to observe that the resolution of an issue of interpretation in a case like the present is an iterative process, involving

“checking each of the rival meanings against other provisions of the document and investigating its commercial consequences”.

Like him, I also think that caution is appropriate about the weight capable of being placed on the consideration that this was a long and carefully drafted document, containing sentences or phrases which it can, with hindsight, be seen could have been made clearer, had the meaning now sought to be attached to them been specifically in mind. Even the most skilled drafters sometimes fail to see the wood for the trees, and the present document on any view contains certain infelicities, as those in the majority below acknowledged… Of much greater importance in my view, in the ascertainment of the meaning that the deed would convey to a reasonable person with the relevant background knowledge, is an understanding of its overall scheme and a reading of its individual sentences and phrases which places them in the context of that overall scheme. Ultimately, that is where I differ from the conclusion reached by the courts below. In my opinion, their conclusion elevates a subsidiary provision for the interim discharge of debts “so far as possible” to a level of pre-dominance which it was not designed to have in a context where, if given that pre-dominance, it conflicts with the basic scheme of the deed.

[Edited for ease of reading. You can find the original case on Westlaw].