David Lorimer

Speaking to Scottish Legal News, David Lorimer, a PhD candidate at Aberdeen University who applies a quantitatively analytical approach to criminal law, said that where there is no means of expressing uncertainty, which research shows to be a function of ‘not proven’, “there is a related increase in the likelihood of miscarriages of justice”.

Mr Lorimer said: “There is a zone of uncertainty around the standard of proof. Not only in terms of its definition but quantitatively.

“Where there is a certain amount of incriminating evidence and it is uncertain as to whether this is enough to put the net weight of evidence ‘beyond reasonable doubt’, ‘not proven’ will signify that uncertainty. The law says the accused must get the benefit of such doubt.”

The Scottish government has published research carried out by Ipsos MORI into the jury system and the effects of removing ‘not proven’.

Mock juries were asked to deliver verdicts in 64 “finely balanced” trials, in which the evidence encouraged discussion of the ‘not proven’ verdict, with the options of ‘guilty’, ‘not guilty’ and ‘not proven’ available to them as they would be in a real trial.

Mr Lorimer said: “If we ask any number of people the question, we may get a ‘finely balanced’ response which could perhaps be, on average, one third affirmatives, one third negatives and one third uncertain.

“Just how definitive of ‘finely balanced’ this suggested split may be is questionable, as there is every possibility that in such cases there will be more uncertainty and thus more not proven votes.”

Removing ‘not proven’, under the exact same circumstances – those of a finely balanced trial – would likely result in an equal split between votes of guilty and not guilty, he explained.

He added: “So, in the first instance we have one third of the people voting affirmative (guilty) and in the second instance, half of the people are voting affirmative.

“A rise in the number of affirmative or guilty votes thus appears to be an inevitability when the not proven vote is removed in a ‘finely balanced’ scenario such as the Ipsos MORI trials.”

The report stated that removing not proven “might lead to more jurors favouring a guilty verdict, which might, therefore, lead to more guilty verdicts over a larger number of trials”.

Mr Lorimer said: “Removing an option that indicates uncertainty at meeting the legal standard of proof, i.e. not proven, will lead to more guilty verdicts.

“Furthermore, a hung jury indicates uncertainty at meeting the legal standard of proof as does anything short of a unanimous verdict.

“Where there is no provision for such expression or demonstration of uncertainty, there is a related increase in the likelihood of miscarriages of justice.”