I do believe it has something to do with a member of the jury, i had a look on judiciary.uk (jury irregularities protocol) and found this (BBM):
Jury Irregularities in the Crown Court: a Protocol issued by the President of the Queen's Bench Division.
A jury irregularity is anything that may prevent a juror, or the whole jury, from remaining faithful to their oath or affirmation as jurors to ‘faithfully try the defendant and give a true verdict according to the evidence’. Anything that compromises the jury’s independence, or introduces into the jury’s deliberations material or considerations extraneous to the evidence in the case, may impact on the jurors’ ability to remain faithful to their oath or affirmation.
Section 10: In relation to the conduct of the trial, the trial judge may:
i) Take no action and continue the trial. If so, the judge should consider giving some explanation to the jurors to reassure them that nothing untoward has happened that need concern them.
ii) Continue the trial but, if appropriate, give a reminder to the jury, tailored to the requirements of the case, that their verdict is a decision of the whole jury as a body and that they should give and take and try to work together. It is, in every case, essential that no undue pressure is exerted on the jury.
iii) Discharge the juror(s) concerned and continue the trial if sufficient jurors remain.The minimum number required to continue is nine: Juries Act 1974, section 16(1). Consideration must be given as to what to say to the remaining jury members when one or more have been discharged and to the juror(s) on discharge.The juror(s) must be warned not to discuss the circumstances with anyone and it may be necessary to discharge the juror(s) from current jury service.
iv) Discharge the whole jury and re-list the trial.Again the jury should be warned not to discuss the circumstances with anyone. Consideration should be given to discharging them from current jury service. If the jury has been discharged and there is a danger of jury tampering in the new trial, the Crown may make an application under s.44 Criminal Justice Act 2003 at a preliminary hearing for a trial without a jury if jury protection measures would be insufficient.
v) If the judge is satisfied that jury tampering has taken place, discharge the jury and continue the trial without a jury: s.46(3) Criminal Justice Act 2003, or discharge the jury and order that a new trial take place without a jury: s.46(5) Criminal Justice Act 2003.
A jury member has been discussing the case outside court or on SM maybe? Or perhaps has some link to the defendant?
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