Just reading this mornings papers online regarding the Vicky Price case having to be retried because the jury couldnt reach a majority verdict. Largely because they didnt understand what was going on.
The Judge has commented that there was a fundamental deficit in understanding. They couldnt even decide and had to ask the judge what 'reasonable doubt' meant 
Notwithstanding a retrial is going to cost the tax payer millions.
Anecdotally - my mate was on a jury at Belmarsh some years ago. All very Tony Hancock sketch, Friday afternoon, they decided on a quick conviction rather than have to come back on Monday because the defendant lived on a notorious estate, therefore if he wasn't guilty of that offence, he was probably guilty of something else he hadn't been caught for
.
Conversely another mate was on a jury up at Southwark. The defendants wife played bingo with my mates mum. She returned a not guilty verdict on that one on the grounds her mum liked the lady 
I do realise that the jury system is probably the best model the world has for a fair and equitable trial, being jusged by your peers etc - but it's just not infallable is it?
I think professional jurors would be the way forward!