This very point was made yesterday by the Supreme Court of Canada: R v Krieger  SCC 47 (26 October 2006). The Court ordered a retrial because, in directing the jury that they must convict, the judge had deprived the accused of the right to trial by jury. Except where the judge directs them to acquit, the verdict must be that of the jury. Depriving the accused of trial by jury was necessarily a miscarriage of justice and required the quashing of the conviction.
The Court approved the views to this effect of Sir Patrick (subsequently, Lord) Devlin in his book “The Judge” (1979), pp 142-143 and 157. He said, at 157, that it doesn’t matter how obvious it may be to the judge that the accused is guilty, the verdict must be that of the jury, and he called this, in an italicised passage, “the first and traditional protection that the law gives to an accused”. The second protection is that, on appeal, a conviction will be quashed if the judges find a “lurking doubt” that they consider the jury has overlooked. Devlin added: “…the second is an addition to the first and not a substitute for it.”
In Krieger, reference was made to Lord Mansfield’s observation in R. v. Shipley (1784), 4 Dougl. 73, 99 E.R. 774, at p. 824:
“It is the duty of the Judge, in all cases of general justice, to tell the jury how to do right, though they have it in their power to do wrong, which is a matter entirely between God and their own consciences.”
I add that readers of Geoffrey Robertson’s “The Justice Game” (1998) will recall his remark that “[t]his remains the most significant feature of English criminal law.” The rule that the decision to convict can only be made by the jury operates, especially in politically-motivated prosecutions, to ensure that “the only enemies of the State who are put in prison are enemies of the people as well.”
That misdirections of this kind should occur reminds us that judges must not be allowed to lose sight of the fundamentals. See also my comments on R v Wang, blogged on 14 February 2005.