A trial judge's direction that 'a reasonable doubt is something which you must examine' and that 'the testing of any doubt lies within your own conscience' constitutes a misdirection by inviting the jury to subject any doubt they entertain to analysis or evaluation to determine its quality. Such a misdirection on the standard of proof goes to the root of the proceedings and constitutes a miscarriage of justice to which the proviso has no application. A specific direction warning against reasoning from rejection of an alibi to guilt is not required where the only evidence capable of proving the alibi false is the same evidence that directly proves the offence.
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