66 In Wardley Australia Ltd v Western Australia  HCA 55; 175 CLR 514 Mason CJ, Dawson J, Gaudron J and McHugh J stated that the Trade Practices Act , s 82(1) (the equivalent of the Fair Trading Act , s 68(1)) should be understood as taking up the common law practical or common sense concept of causation discussed in March v Stramare (E & MH) Pty Ltd  HCA 12; 171 CLR 506. One aspect of that case which remains uncontentious is that causation in terms of legal responsibility does not require the impugned cause to be the sole cause; it must be a cause: March v Stramare at 509. The same obtains in respect of the causation question embedded in the phrase “by conduct” in the provision under consideration: Henville v Walker  HCA 52; 206 CLR 459 at 469  (Gleeson CJ), 480 - (Gaudron J), 493-494 - (McHugh J), 509  (Hayne J) and 507  (Gummow J, agreeing with McHugh J and Hayne J).
67 In all causal inquiries, the legal framework that gives rise to the question is critical: Environmental Agency v Empress Car Co (Abertillery) Ltd  UKHL 5;  2 AC 22 at 29 and 31 (Lord Hoffmann); Chappel v Hart  HCA 55; 195 CLR 232 at 238  (Gaudron J), 255-256 - (Gummow J) and 285  Hayne J; Travel Compensation Fund v Tambree (t/as R Tambree & Associates)  HCA 69; 224 CLR 627 at 642-643  (Gummow J and Hayne J); Kuwait Airways Corporation v Iraqi Airways Co (Nos 4 and 5)  UKHL 19;  2 AC 883 at 1091 - (Lord Nicholls of Birkenhead); Rosenberg v Percival  HCA 18; 205 CLR 434 at 460-461 - (Gummow J); and see Campomar Sociedad, Limitada v Nike International Ltd  HCA 12; 202 CLR 45 at 83-84  and 85  (Gleeson CJ, Gaudron J, McHugh J, Gummow J, Kirby J, Hayne J and Callinan J) and Elbourne v Gibbs  NSWCA 127 at . The legal context and relevant rule of responsibility direct one to the relevant legal policy and purpose of the causal question, thus affecting the evaluation of the extent of the required factual involvement of the impugned act or omission in assessing legal responsibility for the loss. An example of the relevance of the content of the rule of responsibility is the duty of a doctor to warn a patient of material risk inherent in proposed treatment. The causal conclusion of Gummow J in Chappel v Hart was founded upon the nature and purpose of the duty concerning the right to know of the risks in order to make an informed choice at 258 , as were the views of the majority in Chester v Afshar  UKHL 41;  1 AC 134 at 146  (Lord Steyn), 153  and 154  (Lord Hope of Craighead) and 163  (Lord Walker of Gestingthorpe).
68 These are not new concepts. They can be seen to be encompassed within the value judgments and policy considerations referred to by Mason CJ in March v Stramare ; and see also Barnes v Hay (1988) 12 NSWLR 337 at 353 (Mahoney JA) and Fitzgerald v Penn HCA 74; 91 CLR 268 at 278 (Dixon CJ, Fullagar J and Kitto J).
69 The relevance of these considerations to the provisions providing for relief under the Trade Practices Act and its State and Territory companion legislation, such as the Fair Trading Act , can be appreciated from the fact that such legislation is “fundamentally remedial and protective legislation” giving effect to “matters of high public policy”; and is thus to be construed so as to give the fullest relief which the fair meaning of the legislation will allow: Marks v GIO Australia Holdings Ltd  HCA 69; 196 CLR 494 at 528-529 -. These descriptors of the legislation are apt because the legislative purpose is to promote, in the broad sphere of Australian economic activity (trade and commerce), informed commercial activity, not based on misinformation, but rather on accurate information. That purpose goes beyond honest dealing in good faith.
70 In this context, the High Court has been clear that common law analogues for the understanding of application of Acts such as the Fair Trading Act cannot be imposed: Marks v GIO at 503-504 - (Gaudron J), 510  (McHugh J, Hayne J and Callinan J), 528-529 - (Gummow J) and 549  (Kirby J); Henville v Walker at 501-502 - (McHugh J); I & L Securities Pty Ltd v HTW Valuers (Brisbane) Pty Ltd  HCA 41; 210 CLR 109 at 124-125 - (Gaudron J, Gummow J and Hayne J) andMurphy v Overton Investments Pty Ltd  HCA 3; 216 CLR 388 at 407  (Gleeson CJ, McHugh J, Gummow J, Kirby J, Hayne J, Callinan J and Heydon J), though cf Campbell v Backoffice Investments at 341 . One cannot argue from common law premises to a conclusion of the construction or application of relevant provisions of the Act. Earlier cases such as Gates v City Mutual Life Assurance Society Ltd  HCA 3; 160 CLR 1, Wardley and Kizbeau Pty Ltd v WG & B Pty Ltd  HCA 4; 184 CLR 281 must be viewed in the context and light of the later cases.
71 The inquiry is for a sufficient and direct link between the Act and the consequences: see McCarthy v McIntyre  FCA 784 at  (Hill J, Sackville J and Katz J) in order that the purpose and policy of the legislation be vindicated. That policy can be seen to be the upholding of the norm of conduct laid down in s 42, as fundamental and protective legislation.