5.174 The most recent consideration is the decision of the New Zealand Court of Appeal in Vector Gas Ltd v Bay of Plenty Energy Ltd.394
5.175 Two energy companies, both concerned in the New Zealand gas industry, entered into a gas supply agreement in 1995 whereby Vector Gas (then the Natural Gas Corporation of New Zealand Ltd (‘NGC’)) agreed to supply gas to Bay of Plenty Energy Ltd (‘BoPE’) (‘the Agreement’), which was then sold on to a milk-processing plant in Edgecumbe on the Bay of Plenty. In August 2004 NGC gave notice of termination of the Agreement to BoPE. The validity of this notice of termination was the original core of the parties’ dispute, but its legitimacy was upheld by the High Court and Court of Appeal, and no appeal was made in respect of that issue to the Supreme Court. The superficially straightforward issue before the New Zealand Supreme Court was whether a new agreement concluded on 15 October 2004 for NGC to continue to supply gas at a price of NZ$6.50 per gigajoule pending resolution of the termination dispute was inclusive or exclusive of transportation or delivery costs. The letter recording the Agreement did not explicitly address the issue, but referred back to the 1995 agreement, which was inclusive of transportation costs, which supported BoPE’s contention that the proper construction of the Agreement was for an inclusive price. Nevertheless the New Zealand Supreme Court unanimously preferred NGC’s contention that the price was exclusive of transportation costs. The difference between the two parties was worth some $3 million. The five judges reached the same destination by a variety of different routes, which each requires sensitive analysis.
5.176 In summary, two of the judges considered the meaning of the 15 October letter (and in particular the word ‘supplied’) to be plain and unambiguous (McGrath and Wilson JJ), agreeing with the Court of Appeal that it meant an inclusive price. Tipping J disagreed, and insisted that it was ambiguous, whether viewed in isolation or in context. The other two judges were more non-committal, with Blanchard J inclining to the view that it probably meant an inclusive price. Four of their Honours thought that regard could be had to background evidence, without a threshold of ambiguity having to be crossed. Wilson J seriously disagreed, reasserting traditional ‘plain meaning rule’ thinking and the need for an ambiguity threshold. Blanchard and Gault JJ thought that recourse could be had to the correspondence through the ‘subject matter rule or exception’. In doing so they disagreed with McGrath J, who defined the subject-matter rule (p. 258) more narrowly, and did not think that it could assist in determining the price here. Neither Tipping J nor Wilson J invoked this rule either way. For Wilson J, recourse was only possible to the correspondence via the estoppel-by-convention exception. Three of the judges employed estoppel by convention as an alternative ratio: Tipping, McGrath, and Wilson JJ. All the judges appeared to think that the inclusive price construction made no commercial sense.
5.177 On prior negotiations and subsequent conduct, the court split in three (or possibly four) directions. Blanchard and Gault JJ considered that it was not necessary to consider the issue on this occasion. McGrath J considered that the House of Lords had got it right in Chartbrook, and that the exclusionary rule should continue, subject to the legitimate safety valves of rectification and estoppel by convention. Both Tipping and Wilson JJ concluded that Prenn v Simmonds should be abandoned, and that all relevant evidence of prior negotiations and subsequent conduct should be admitted and weighed. Wilson J’s liberal stance on this has to be counterbalanced by his conservative restatement of the plain meaning rule. Tipping J revisited his Gibbons opinion, and his ‘shared or mutual’ restriction on evidence of subsequent conduct. His Honour abandoned it in favour of the objective principle. Wilson J took the same line.
5.178 It is necessary to set out the correspondence leading up to 15 October 2004 in a little more detail, although different judges had recourse to the correspondence on different legal bases. On 28 September 2004 NGC offered BoPE a range of options for the future supply of gas including an offer that gas could be purchased at NZ$6.50 per gigajoule. That letter was explicit that ‘transportation and metering rates’ were not included, and would need to be discussed taking into account historic usage and posted prices. On 5 October BoPE’s solicitors responded, rejecting the offer and intimating that proceedings were imminent on the termination issue. It noted that NGC had acknowledged that it had gas to supply at NZ$6.50 per gigajoule. The letter continued with a proposal that in lieu of BoPE ‘having to apply for injunctive relief’, NGC should agree to continue to supply gas ‘on the basis of the Agreement’ pending resolution of those proceedings. Correspondingly BoPE would undertake in the event that its proceedings were discontinued or were unsuccessful to pay for each gigajoule ‘the difference between the Agreement price and NZ$6.50 (or the current market price, whichever is lower), plus interest’. This became the basis of the Agreement recorded in correspondence on 15 October that BoPE agreed in the event that its proceedings were discontinued or were unsuccessful to pay ‘for each GJ supplied, the difference between the price set out in the Agreement and $6.50 per GJ’, plus interest as per the Agreement.
5.179 In the most important judgment, Tipping J insightfully observed that: ‘Some of the difficulties in this area may derive from the concept of “prior negotiations” being employed in a more or less expansive way.’ His Honour continued:
5.180 It is submitted that that is far more consistent with the classical authorities than many more recent authorities, and properly deploys the objective principle to determine which pre-contractual material is available. Tipping J was clear:
The recent English conversion to pragmatic or policy-based reasons for excluding otherwise relevant evidence was thus rejected.
5.181 Critically Tipping J explicitly retreated from his earlier judgment in Gibbons Holdings Ltd v Wholesale Distributors Ltd 397 (which is considered further below) which had insisted on a ‘shared or mutual’ intention precondition to admitting evidence. Accordingly evidence which did not cross the line between the parties, or otherwise demonstrated mutuality, was not relevant. However Tipping J’s second thoughts were that the governing criterion was to be straightforwardly the objective principle:
Tipping J reviewed the earlier correspondence and concluded:
5.182 Wilson J, whilst puzzlingly attempting to reassert the ambiguity threshold, also accepted the nineteenth-century approach that if ambiguity was established all the evidence becomes available, including declarations of subjective intent (but not ‘undeclared intent’).400 Having commenced with a conservative, nay reactionary, stance, the tone of Wilson J’s judgment then turned more radical:
5.183 If His Honour had been in the court in Gibbons Holdings Ltd v Wholesale Distributors Ltd 402 (he was successful counsel) he would have joined the majority on the question of principle, and would not have imposed a ‘shared or mutual’ intention restriction. Whether the evidence crossed the line or was mutual went to weight, not admissibility. Wilson J would have admitted the evidence here on the basis of his estoppel exception. It is submitted that the approach of both Tipping and Wilson JJ now approximates to that adopted by Thomas J in Gibbons.
5.184 Blanchard J, with whom Gault J agreed, delivered a succinct judgment. First, His Honour considered the ordinary meaning of ‘supplied’, and suggested that it was perhaps more likely to be indicative of an inclusive price. Secondly, the context of the agreement was the proposed interim order application to ensure that supply continued. The quid pro quo of the court granting that order would have been BoPE’s undertaking in damages to NGC for the loss it would suffer if its argument that it was entitled to refuse to supply eventually succeeded. Such loss would be measured by prevailing market rates which in October 2004 were on average $6.68 plus transmission costs.403 Thirdly, recourse to that background (which is always possible without the need to prove ambiguity) demonstrated that the agreement was ambiguous, and furthermore that in the context of ‘an interim settlement of an aspect of larger dispute about supply under the 1995 Agreement’404 BoPE’s suggested inclusive price construction was ‘exposed as commercially absurd’.405
(p. 261) 5.185 Moving beyond the immediate context to the parties’ negotiations recorded in the correspondence, Blanchard J noted the confirmation of the exclusionary rule in Chartbrook Ltd v Persimmon Homes Ltd406 and that it appeared to continue to hold sway in Australia,407 but insisted that the rule was not without exception. These included the recourse to the negotiations ‘not in order to provide a gloss on the terms of the contract, but rather to establish the parties’ knowledge of the circumstances with reference to which they use the words in the contract’.408 In addition, it embraced the genesis, the background, and the market. Critically it included the ‘subject-matter exception’, which also in part defined the commercial object of the transaction. Here Blanchard J (with Gault J agreeing), expressly differed from the narrower approach to the ‘subject-matter exception’ adopted by McGrath J. In Blanchard J’s view:
5.186 On the basis of that broad approach to subject-matter there was no need to examine the broader issue of principle: ‘The question of how much further the courts of this country should go towards admitting evidence of negotiations for the light they may shed on the objective intention of the parties can be left for another day.’410
Accordingly, Blanchard and Gault JJ appear to have decided that the immediate context, genesis, or purpose of the agreement (obviating the need for an injunction hearing) were sufficient to demonstrate that the inclusive price construction was commercially absurd. Furthermore, that conclusion was ‘reinforced’ if reference were made to the correspondence leading up to the agreement, which was admissible on the basis of the subject-matter exception: it demonstrated what the supply of gas consisted of.
5.187 Of the five judges, only McGrath J endorsed the conservative English rejection of any liberalization in Chartbrook:
5.188 Furthermore, McGrath J took a very restrictive view of the ‘subject-matter rule’. The earlier correspondence was inadmissible because McGrath J considered the meaning of the final letter to be unambiguous. No relevant exception applied:
This is far too limited an account of subject-matter, as Blanchard and Gault JJ made clear. It can be contrasted with the nineteenth-century authorities we have discussed. Evidence should have been admitted to see whether the subject-matter was ‘gas without delivery’ or ‘gas with delivery’. However McGrath J was consistent with the conservative position, and reached the same result via the legitimate safety device of estoppel. The pre-contractual material was inadmissible for the purpose of construction, but was admissible for the purposes of estoppel, and on that basis BoPE was estopped from denying that it had agreed to a price exclusive of transmission costs.413