Dr Theodora Dallas, a 34-year old juror who researched a defendant on the internet and shared the information with fellow jurors during the trial, has been jailed for six months for contempt of court.
The decision raises serious questions over how online information and social media is governed among jurors. Journalists were recently allowed to use Twitter in court during Wikileaks boss Julian Assange's extradition hearings, and information on major cases is hard to avoid when using the internet or switching on the television.
Jurors are explicitly informed in court not to consult media reports or the internet in general around a case, until it is finished. But many do not understand the implications of doing so, or overlook some of the instructions at a later date.
Dallas, a psychology lecturer at the University of Bedfordshire, is Greek and has said her grasp of some technical English is not good. She told the judges she had "no intention" of influencing the jury, in the assault case in a Luton court last year.
"I did not understand that I could make no search on the internet," she said. "I really apologise. I never thought it would cause such disruption."
In July 2011, after Dallas was discovered to have researched the defendant on the internet, and shared the information with other jurors, the trial was stopped.
She is likely to serve three months in prison, but be on probation for the other six months, according to the High Court judge who issued the ruling.
Lord Judge, Lady Justice Hallett, said Dallas had "deliberately disobeyed" juror instructions. "Misuse of the internet by a juror is always a most serious irregularity and an effective custodial sentence is virtually inevitable."