It is unnecessary for the purposes of this case to discuss the many decisions in which the principles stated in Makin v. Attorney-General (N.S.W.) have been expounded and exemplified. The most notable recent exposition is contained in the judgments of the House of Lords in Reg. v. Boardman [11] . The first principle, which is fundamental, is that the evidence of similar facts is not admissible if it shows only that the accused had a propensity or disposition to commit crime, or crime of a particular kind, or that he was the sort of person likely to commit the crime charged. The second principle, which is a corollary of the first, is that the evidence is admissible if it is relevant in some other way, that is, if it tends to show that he is guilty of the crime charged for some reason other than that he has committed crimes in the past or has a criminal disposition. The concluding words of the statement cited from Makin v. Attorney-General (N.S.W.) should be regarded only as giving examples of the second principle which is there stated; there is no "closed list of the sort of cases in which the principle operates": Harris v. Director of Public Prosecutions [12] . Moreover the words of that statement do not mean that the admissibility of the evidence depends on the line taken by the defence at the trial, that is, on whether the accused has raised or disclaimed a particular defence: Harris v. Director of Public Prosecutions [13] . It is often difficult to decide whether a particular piece of evidence is or is not admissible within these principles. However when in doubt a judge should remember that the admission of similar fact evidence is the exception rather than the rule. To be admissible the evidence must have "a strong degree of probative force" (per Lord Wilberforce in Reg. v. Boardman [14] , or "a really material bearing on the issues to be decided" (per Lord Morris of Borth-y-Gest [15] , citing Harris v. Director of Public Prosecutions [16] ; it may not be going too far to say that it will be admissible only if it is "so very relevant that to exclude it would be an affront to common sense" (see per Lord Cross in Reg. v. Boardman [17] ; and see per Lord Hailsham of St. Marylebone [18] ). The question is thus one of degree, and in answering it the judge must apply his experience and common sense. Although the judgment which the judge is required to make is to some extent discretionary, the rule of exclusion is a rule of law and not of discretion, and the principle allowing the admission of the evidence remains subject to the discretionary power to exclude it, even if legally admissible, where its prejudicial effect outweighs its probative value. In applying the test of admissibility to which I have just referred, practical assistance, in may cases, will be obtained by considering whether there is a "striking similarity" between the similar facts and the facts in issue (see Reg. v. Boardman [19] ).