Juror misconduct and internet publications - (pdf 141 pages) - which includes a recommendation for a new criminal offence for jurors conducting prohibited research. In total, the report contains 31 recommendations.
Clearly, a case must be decided on the basis of the evidence presented to the court and extraneous material should not be taken into account - The Guardian - Law Commission floats plans to stop jurors researching cases online.
In recent times, a number of jurors have been punished for contempt of court.
As David Banks points out in an article in The Guardian - there were 17,786 jury trials in England and Wales in 2011. Only a small number of jurors have been convicted of contempt of court where their conduct has involved using the internet. Banks provides links to some examples including Joanne Fraill - see Attorney-General v Fraill and Sewart  EWCA Crim 1570 (previous post 25th July 2011).
The The Guardian - Theodora Dallas case is of interest since it is proceeding to the European Court of Human Rights - BBC 5th December 2013. Dallas argues that the judge had not been clear about using the internet or that doing so could be a criminal offence. The Guardian's article on this case also notes: In a written witness statement to the judges, Dallas admitted that "sometimes my grasp of English is not that good". That, in itself, raises a further and separate issue about the need for good understanding of the English language by jurors.
A study by UCL has indicated that 23% of jurors are unclear about the rules
surrounding internet use during a trial. However, Professor Cheryl Thomas said - “These
findings show that the vast majority of jurors understand and follow the rules
on how jurors can use new media during trial but the message is not getting
through and is confusing to a significant minority of jurors."
The Crown Court Benchbook (2010) Chapter 2 states:
The jury will be asked to return a unanimous verdict. It is their collective view of the evidence which will alone determine their verdict. They should discuss the evidence only when all 12 jurors are preset in the jury room.
For the same reason, jurors should not discuss the case with anyone, not least family and friends whose views the trust, when they are away from court, either face to face, or over the telephone, or over the internet via chat lines or, for example, Facebook or MySpace. If they were to do so they would risk disclosing information which is confidential to the jury. Each juror owes a duty of confidentiality to the others, to the parties and to the court. Furthermore, if they were to discuss the case with others they would risk consciously or not, bringing someone else's views to their consideration of the evidence ........
If the case is one which has in the past or may during the trial attract media attention, the jury should remember that the report is only the author's version of past events. It is the jury alone which hears the evidence upon which they must reach their verdict. They should therefore take care to ensure that they do not allow such second-hand reporting or comment to influence their approach to the evidence.
We have a system of open justice in which the parties themselves decide what evidence to adduce at trial. It is upon that evidence alone that the jury must reach their verdict. They should not seek further information about, or relevant to, the case from any source outside court, including the internet (e.g. Google). If they were to do so it would be unfair to the prosecution and the defence because neither would be aware of the research and its results and, therefore, neither would be aware of the research and its results and, therefore, would be unable to respond to it.