For the professional lifetime of most of us in practice, the test for dishonesty in offences under the Theft Acts was that set out in Ghosh (1982) 75 Cr.App.R. 154 – a defendant was only proved to have been dishonest if, firstly, what he had done was dishonest by the ordinary standards of reasonable and honest people and, secondly, he realised that what he was doing was by those standards dishonest.
As is well known, the Supreme Court, in a civil case in 2017 (Ivey v Genting Casinos UK Ltd (Trading as Crockford’s Club)  UKSC 67), ruled that Ghosh did not correctly represent the law and that the test it there identified should henceforth be applied in both civil and criminal cases. That test is that the tribunal of fact should first ascertain (subjectively) the defendant’s knowledge or belief as to the facts, and once that is established (there is no additional requirement of reasonableness, although that might well go to whether the belief was in fact held), the question of whether his conduct was dishonest was to be determined by applying the (objective) standards of ordinary decent people.
As to whether that test should be applied in criminal proceedings, however (as the Supreme Court said it should), the ruling was strictly obiter. As early as DPP v Patterson  EWHC 2820 (Admin) the President of the QBD stated that, given the unanimous observations of the Supreme Court, it was difficult to imagine the Court of Appeal preferring Ghosh to Ivey, but until now the Court of Appeal (Criminal Division) had made no binding ruling.
That has now changed. On 29th April, in R v Barton, R v Booth  EWCA Crim 575, a very strong five-judge Court of Appeal (including the Lord Chief Justice, the President of the QBD and the Vice-President of the Court of Appeal (Criminal Division)), duly preferred Ivey. In doing so, it made some interesting comments about the doctrine of precedent, but practitioners can now be confident, in advising their clients and in addressing courts, that it is the Ivey test that applies.