Does the Vicky Pryce trial suggest jurors are getting less intelligent?
The ex-wife of former cabinet minister Chris Huhne faces a retrial after the jury was discharged by the judge, who said there was a "fundamental deficit in understanding" of the trial process. But is it an isolated incident, or are juries becoming less intelligent?
Barrister John Cooper told the BBC's Newsnight programme: "Jurors sometimes ask questions; sometimes they get it right and sometimes they get it wrong."
He once appeared in a trial where the jury asked if they could base their verdict on "gut instinct".
But the Vicky Pryce trial jury at Southwark Crown Court seems to have been exceptional. The trial judge, Mr Justice Sweeney, said: "In 30 years of criminal trials I have never come across this at this stage, never."
The 10 questions posed by the jury shocked many and have been widely reproduced on news sites and newspapers.
One of them was: "Can a juror come to a verdict based on a reason that was not presented in court and has no facts or evidence to support it either from the prosecution or defence?"
The judge said some of the questions being asked by the jury demonstrated a "fundamental deficit in understanding" of the trial process and the role of the jury.
It is not the first time the jury system has been called into question.
In 1993, a man was jailed for life for murdering Harry and Nicola Fuller, in East Sussex. Stephen Young's conviction was thrown out after it emerged that four jurors had consulted a ouija board to contact the dead. He was convicted again after a retrial.
In 2010, the Ministry of Justice commissioned research into jury behaviour. It found that a third of jurors failed to correctly identify the key issues in a trial.
But there's no evidence that juries are becoming less intelligent, says Prof Cheryl Thomas, who carried out the research.
"One thing we do know is that juries are more representative of the wider population than they used to be. Prior to 1972 you could only sit on a jury if you owned a house or were the named tenant, which tended to exclude women and younger people. It was felt to be unfair and biased," she said.
In 2004, the government changed the rules to make it harder to avoid jury service, removing the automatic exclusion for certain professions, such as doctors. In 2001, then Home Secretary David Blunkett had argued that "middle class withdrawal from jury service" had to be stopped.
But changes to selection rules did not necessarily make juries cleverer.
"We found it was simply not true that the more important and clever got out of jury service before or after. In fact high earners have the highest rate of jury service," said Prof Thomas.
The notion that juries are dominated by retired and unemployed people is a myth, she insists.
There is of course no test of intellectual ability for those sitting on a jury. The idea underpinning a legal system where a jury is made up of one's "peers" is that court cases should be understandable to the average person.
Some commentators have questioned whether some kind of discretion could be introduced to the selection process. Writing in the Daily Mail, Melanie Phillips said there might be a case "for some kind of basic testing of jurors' cognitive abilities".
There are restrictions in place. People who could not understand English were not asked to sit on juries and there was an also an exclusion for some people who had suffered mental health problems, says Prof Thomas.
One of her findings in 2010 was that many jurors wanted more guidance on how they should conduct their deliberations and this has resulted in some new guidance on jury deliberation, which is currently being used on a trial basis at a number of courts.
The idea of dispensing with juries in some cases was suggested in 2005, after the collapse of the £60m Jubilee Line fraud trial.
There was no suggestion that the jury in that case was unintelligent, far from it, it was suggested that the 13-month trial was so fiendishly complex that even Mensa members would have struggled.
But the Fraud (Trials Without A Jury) Bill died a death after being blocked in the House of Lords by peers who felt the right to a jury trial was sacrosanct.
And there is still a consensus that whatever its flaws, the jury system is an effective one.
"The alternative is more frightening," says Mr Cooper. "The alternative is no jury and not being tried by our peers, but by a judge."