22 In R v Tatnell [1962] Qd R 11 at 14, Hanger J (with whom Mansfield CJ agreed) held that:
These cases seem to me ample authority for a proposition that, though the prisoner in fact announced a plea of guilty to a charge, yet where he makes statements, at the time or before sentence, which show that…he alleges facts which would amount to a defence to the charge, then in these circumstances, he should be treated as pleading not guilty .
23 In R v GV [2006] QCA 394 at [37], the Queensland Court of Appeal summarized the effect of the authorities on this point to be that:
…a plea of guilty which is not in plain, unambiguous and unmistakeable terms must be treated as a plea of not guilty, and further that where, on a plea of guilty, a defendant so qualifies the plea by giving an explanation in relation to the matter with which he has been charged, he should be taken to be pleading not guilty.
24 In R v Marchando (2000) 110 A Crim R 337 at [4] Simpson J (with whom the other members of the NSW Court of Criminal Appeal agreed) said:
The relevant legal principles are neither complicated nor controversial. The court has a discretion to permit a change of plea at any time prior to sentence: R v Griffiths (1977) l37 CLR 293 at 335; Chow v DPP (1992) 28 NSWLR 593 at 599. Leave, while a discretionary matter, should readily be granted where the plea has been entered pursuant to some material mistake, or in circumstances where its integrity is otherwise questionable; R v Sagiv (1986) 22 A Crim R 73. Circumstances that warrant the exercise of discretion in favour of permitting the change of plea include lack of appreciation on the part of the defendant of the nature of the charge; absence of evidence sufficient to convict the defendant; fraud or threats or other impropriety inducing the plea: R v Boag (1994) 73 A Crim R 35; or, more generally, a miscarriage of justice for other reasons: R v Chiron [1980] 1 NSWLR 218 at 235. The last mentioned case establishes that a miscarriage of justice justifying the grant of leave to withdraw a plea of guilty may be established, inter alia, where the decision to enter the plea resulted from an erroneous ruling on the admissibility of evidence. The central question in all cases is whether it has been shown - the onus lying on the applicant - that the plea was not really attributable to a consciousness of guilt: R v Davies (1993) 19 MVR 481.
25 The following principles, in my view, are supported by these authorities:
(a) the Court must accept a plea of guilty which is unequivocal and not made in circumstances suggesting that it is not a true admission of guilt (those circumstances include ignorance, fear, duress, mistake or the desire to gain a technical advantage). If a plea of guilty is equivocal the Court must enter a plea of not guilty. However, ordinarily, a plea of guilty is not finally accepted by a court until sentence has been passed. See Maxwell at 511, Foster , R v Jerome and McMahon, R v Tatnel, R v GV.
(b) a person is free to plead guilty even if he is not, and may do so for all manner of reasons (for example, to avoid worry, inconvenience or expense; to avoid publicity; to protect family or friends; or in the hope of obtaining a more lenient sentence than if convicted after a plea of not guilty). It is not a miscarriage of justice for the court to act on an unequivocal, freely made plea of guilty even if the person is not guilty: Meissner at 141, 157.
(c) if the trial judge forms the view that the evidence does not support the charge or that for any other reason the charge is not supportable, he should advise the defendant to withdraw the plea and plead not guilty; but he cannot compel the defendant to do so: Maxwell at 510.
(d) the court has a discretion to permit a change of plea at anytime prior to sentence if it would be a miscarriage of justice not to do so: R v Marchando at [4].
26 It is unclear, to my mind, what the scope of the distinction is between the "desire to gain a technical advantage" which is a circumstance suggesting that it is not a true admission of guilt (Maxwell at 511), and on the other hand, permissible reasons for a person to plead guilty when he or she is not guilty which include the "hope of obtaining a more lenient sentence than he would if convicted after a plea of not guilty" (Meissner at 157).
Conclusion
27 The authorities draw a distinction between the duty of the Court to enter a plea of not guilty when faced with an equivocal plea of guilty, and the discretion of the Court to permit an unequivocal plea of guilty to be changed. However, it is not clear to me that the Court has power to reject an unequivocal, freely made plea of guilty to which a defendant unequivocally and freely wishes to adhere. That is the present case. According to Meissner, a person is entitled to plead guilty even if he is not and may do so for all manner of reasons. According to Maxwell (per Dawson and McHugh JJ), a trial judge cannot compel a defendant to change his plea of guilty to not guilty even if the trial judge forms a view that the evidence does not support the charge or that for any other reason the charge is not supportable. It may be that there is such a power at least where the plea of guilty is in order to gain an impermissible "technical advantage" (Maxwell at 511).