Masterton Homes Pty Ltd v Palm Assets Pty Ltd  NSWCA 234 is a case about the construction of partly written and partly oral contracts, and the application of the parol evidence rule to them. Justice of Appeal Campbell summarised the cases in one of those beautifully crafted little numbered lists that this little newspaper regards fondly. Truly, these little numbered lists of principles supported by authority are a labour of love and they are worth sharing. His Honour said:
(1) When there is a document that on its face appears to be a complete contract, that provides an evidentiary basis for inferring that the document contains the whole of the express contractual terms that bind the parties: Gillespie Brothers & Co v Cheney, Eggar & Co  2 QB 59 at 62 per Lord Russell of Killowen CJ; Gordon v Macgregor  HCA 26; (1909) 8 CLR 316 at 319-20 per Griffith CJ (with whom O’Connor J agreed), at 322-3 per Isaacs J; Hoyt’s Pty Ltd v Spencer  HCA 64; (1919) 27 CLR 133 at 143-4 per Isaacs J (with whom Rich J agreed); Maybury v Atlantic Union Oil Co Ltd  HCA 89; (1953) 89 CLR 507 at 517 per Dixon CJ, Fullagar and Taylor JJ; State Rail Authority (NSW) v Health Outdoor Pty Ltd (1986) 7 NSWLR 170 at 191G-2C per McHugh JA (with whom Kirby P at 172G-3C and Glass JA at 180G agreed on this point); Branir Pty Ltd v Owston Nominees (No 2) Pty Ltd  FCA 1833; (2001) 117 FCR 424 (FC) at 505-6 – , 509  per Allsop J (with whom Drummond and Mansfield JJ agreed); Jessop v McInteer  QCA 170 (FC) at  per Muir J (with whom Fryberg J agreed).
(2) It is open to a party to prove that, even though there is a document that on its face appears to be a complete contract, the parties have agreed orally on terms additional to those contained in the writing: Gillespie Brothers at 62 per Lord Russell of Killowen CJ; Gordon v Macgregor at 319-20 per Griffith CJ, at 323 per Isaacs J; Hoyt’s v Spencer at 143-4 per Isaacs J; Hope v RCA Photophone of Australia Pty Ltd  HCA 90; (1937) 59 CLR 348 at 357 per Latham CJ; Maybury v Atlantic Union Oil at 517 per Dixon CJ, Fullagar and Taylor JJ; Health Outdoor at 191D-F per McHugh JA; Carmichael v National Power Plc  UKHL 47;  1 WLR 2042;  4 All ER 897 (UKHL) at WLR 2047B-D, F-H; All ER 901e-g, 901j-2b per Lord Irvine of Lairg LC (with whom Lords Goff of Chieveley, Jauncey of Tullichettle and Browne-Wilkinson agreed), at WLR 2049C-D, 2050B-D; All ER 903e-g, 904e-h per Lord Hoffmann (with whom Lords Goff of Chieveley and Jauncey of Tullichettle agreed); Saad v TWT Ltd  NSWCA 199 at 6 per Handley JA (with whom Priestley and Powell JJA agreed); Jessop v McInteer at  per Muir J; Equuscorp Pty Ltd v Glengallan Investments Pty Ltd  HCA 55; (2004) 218 CLR 471 at 483-4 –  per Gleeson CJ, McHugh, Kirby, Hayne and Callinan JJ. Conversely, it is open to a party to prove that the parties have orally agreed that a document should contain the whole of the terms agreed between them: NSW Cancer Council v Sarfaty (1992) 28 NSWLR 68 at 77A-B per Gleeson CJ and Handley JA.
(3) The parol evidence rule applies only to contracts that are wholly in writing, and thus has no scope to operate until it has first been ascertained that the contract is wholly in writing: Turner v Forwood  1 All ER 746 (EWCA) at 749F per Denning LJ; Heath Outdoor at 191E, 192A-C per McHugh JA; Norwest Beef Industries Ltd v Peninsular and Oriental Steam Navigation Co (1987) 8 NSWLR 568 at 570B-C per Hope JA (with whom Samuels JA agreed); NSW Cancer Council v Sarfaty at 76G per Gleeson CJ and Handley JA; Branir v Owston Nominees at 508  per Allsop J; County Securities Pty Ltd v Challenger Group Holdings Pty Ltd  NSWCA 193 at  per Spigelman CJ; Nicolazzo v Harb  VSCA 79 at  per Dodds-Streeton JA (with whom Ashley and Neave JJA agreed).
(4) Where a contract is partly written and partly oral, the terms of the contract are to be ascertained from the whole of the circumstances as a matter of fact: Moore v Garwood  EngR 1122; (1849) 4 Exch 681 at 689-90;  EngR 1122; 154 ER 1388 at 1391-2; 80 RR 738 at 745-6 per Patteson J delivering the judgment of the Court of Exchequer Chamber; Stones v Dowler (1860) 29 LJ Ex 122 at 124; 121 RR 882 at 884 per Martin B; Bolckow v Seymour  EngR 873; (1864) 17 CB NS 107; 144 ER 43; 142 RR 272 at CB NS 121-2; ER 49; RR 282 per Byles J, at CB NS  EngR 1021; 122; ER 49; RR 282 per Keating J; Palmer v Bank of Australasia (1895) 16 NSWLR (L) 219 at 223-4 per Darley CJ, Windeyer and Cohen JJ (affirmed on a different ground on appeal to the Privy Council in Bank of Australasia v Palmer  AC 540); Deane v The City Bank of Sydney  HCA 44; (1904) 2 CLR 198 at 209 per Griffith CJ, Barton and O’Connor JJ; J Evans & Son (Portsmouth) Ltd v Andrea Merzario Ltd  1 WLR 1078 at 1083E-F;  2 All ER 930 at 935a-b (EWCA) per Roskill LJ; Handbury v Nolan (1977) 13 ALR 339 (HCA) at 341 per Barwick CJ, 348-9 per Jacobs J, (Aickin J agreed with both Barwick CJ and Jacobs J), at 346 per Stephen J (but dissenting as to whether the evidence established a partly written and partly oral agreement), (Gibbs J agreed with Stephen J); Finucane v NSW Egg Corporation (1988) 80 ALR 486 (FCA) at 520-1 per Lockhart J; Carmichael v National Power at WLR 2049C-50E; All ER 903f-4h per Lord Hoffmann; Lewison, The Interpretation of Contracts, 4th ed (2007) Sweet & Maxwell at [4.02] and cases there cited. Similarly, finding the terms of a wholly oral contract is a question of fact: Gardiner v Grigg (1938) 38 SR (NSW) 524 at 532 per Jordan CJ (with whom Nicholas J agreed); Torbett v Faulkner  2 TLR 659 (EWCA) at 661 per Romer LJ; Handbury v Nolan at 346 per Stephen J (with whom Gibbs J agreed); Maggs v Marsh  EWCA Civ 1058;  BLR 395 at  per Smith LJ (with whom Moses and Hallett LJJ agreed).
(5) In determining what are the terms of a contract that is partly written and partly oral, surrounding circumstances may be used as an aid to finding what the terms of the contract are: Stones v Dowler at LJ Ex 124; RR 884 per Martin B; Deane v The City Bank of Sydney at 209 per Griffith CJ, Barton and O’Connor JJ; Handbury v Nolan at 341-2 per Barwick CJ, at 346 per Stephen J, at 348-9 per Jacobs J; Liverpool City Council v Irwin  UKHL 1;  AC 239 at 253C-E per Lord Wilberforce. If it is possible to make a finding about what were the words the parties said to each other, the meaning of those words is ascertained in the light of the surrounding circumstances: Deane v The City Bank of Sydney at 209; Handbury v Nolan at 341-2, 346, 348-9. If it is not possible to make a finding about the particular words that were used (as sometimes happens when a contract is partly written, partly oral and partly inferred from conduct) the surrounding circumstances can be looked at to find what in substance the parties agreed: County Securities v Challenger Group Holdings at - per Spigelman CJ.
(6) A quite separate type of contractual arrangement to a contract that is partly written and partly oral is where there is a contract wholly in writing and an oral collateral contract: J Evans & Son v Anthony Merzario at WLR 1083C-E; All ER 934h-5a per Roskill LJ, at WLR 1084H; All ER 936c per Geoffrey Lane LJ; Hoyt’s v Spencer at 144-5 per Isaacs J; Equuscorp v Glengallan Investments at 484  per Gleeson CJ, McHugh, Kirby, Hayne and Callinan JJ.’