I have approached dishonesty as guided by Lord Hughes in Ivey v Genting Casinos (UK) Ltd [2017] UKSC 67, [2018] AC 391, at [74]: “74. … When dishonesty is in question the fact-finding tribunal must first ascertain (subjectively) the actual state of the individual’s knowledge or belief as to the facts. The reasonableness or otherwise of his belief is a matter of evidence (often in practice determinative) going to whether he held the belief, but it is not an additional requirement that his belief must be reasonable; the question is whether it is genuinely held. When once his actual state of mind as to knowledge or belief as to facts is established, the question whether his conduct was honest or dishonest is to be determined by the fact-finder by applying the (objective) standards of ordinary decent people. There is no requirement that the defendant must appreciate that what he has done is, by those standards, dishonest.”
— R. Knowles CBE. FRN v. Process & Industrial Developments Limited [2023] EWHC 2638 (Comm)