Court-based tweeting is likely to increase the risk of a mistrial and misuse of the internet by jurors must stop if the jury system is to survive, the country's most senior judge said.
Lord Judge, the Lord Chief Justice, warned it was all too easy for campaigners to bombard the micro-blogging site Twitter with messages in a bid to influence the outcome of a hearing.
"We cannot stop people tweeting, but if jurors look at such material, the risks to the fairness of the trial will be very serious, and ultimately the openness of the trial process on which we all rely would be damaged," he said.
"We have to remember that tweets stay on the internet and to allow court-based tweeting is likely to increase the potential for prejudicial material regarding a defendant or a witness to become available on the internet."
He added: "We welcome advances in technology, provided that we are its masters and it is our tool and servant."
Lord Judge questioned whether the text-based transmission of material from a courtroom should be banned, saying he could find no statutory prohibition on its use, but tape recordings were banned under the Contempt of Court Act.
"Why is Twitter in the form of text-based transmission of material from court any different?" he asked.
"This question has yet to be decided, and the decision may have a considerable impact on our processes."
The top judge in England and Wales also called for tougher warnings for jurors over their use of the internet during trials.
"I have to be blunt about this, but in my view if the jury system is to survive as the system for a fair trial in which we all believe and support, the misuse of the internet by jurors must stop," he said.
"I think we must spell this out to them yet more clearly."
Information on the consequences of misusing the internet must be given to every juror, must be reflected in the video which jurors see before they start a trial and judges must continue to direct juries "in unequivocal terms from the very outset of the trial", he said.
He also called for notices in jury rooms which identify "potential contempt of court arising from discussions outside the jury room of their debates to be extended to any form of reference to the internet".
Lord Judge went on: "We cannot accept that the use of the internet, or rather its misuse, should be acknowledged and treated as an ineradicable fact of life, or that a Nelsonian blind eye should be turned to it or the possibility that it is happening.
"If it is not addressed, the misuse of the internet represents a threat to the jury system which depends, and rightly depends, on evidence provided in court which the defendant can hear and if necessary challenge."
Lord Judge said it may be necessary for judges to back up their directions to jurors not to look up their case on the internet with "an express warning that breach of the order might constitute a contempt of court", punishable by a maximum two-year jail sentence.
He also asked whether jurors should be warned that "one day it may become necessary to deal with it as if it is (contempt), and then to treat it with the seriousness it requires, depending on the consequences to the ongoing trial".
Such consequences are much more than the need to discharge a juror or the jury, he said.
The further financial cost of a retrial, the problem of an increased number of retrials and the cost of delays for witnesses, victims and defendants all need to be considered.
"These are significant costs. They cannot be counted in pound notes, but, as you know, the emotional trauma will be considerable."
He added: "What we seem to do at the moment is to assume that the occasions when jurors go to the internet for information are rare indeed. It is therefore easy to brush them aside as odd moments of aberration.
"I wonder whether we will still be thinking that in a year or two from now."
Lord Judge was speaking after Lord Macdonald, the former director of public prosecutions, suggested judges were "giving up" trying to stop juries using Google, Facebook and Twitter to access potentially false and prejudicial information about defendants.
"In essence, we're finally giving up and just concluding that you have to expect juries to try cases fairly and they're told to do that so I think this is a serious issue around privacy, because policing the internet is really, I think, an unmanageable task," the Liberal Democrat peer told the Guardian.
"I don't think juries should be 'allowed' to do online research. But I do think we need to assume this will occasionally happen and that it should not invalidate a trial."
Speaking at the Judicial Studies Board in Belfast on Tuesday, Lord Judge also warned that schools were failing to train children to "sit still and listen for prolonged periods", an essential skill for jurors.
Referring to his teenage grandchildren, he said: "Much of their school work is done by absorbing information from machines. They consult and refer to the internet. When they do so they are not listening.
"They do not, as we did, sit in class for 40 minutes listening to the masters and mistresses providing us with information.
"They are provided with information in written form, which they assimilate into their own technology.
"Now what this form of education lacks is training in the ability to sit still and listen, and I emphasise, listen and think, I repeat, listen and think simultaneously, for prolonged periods.
"Yet that is an essential requirement for every juror."
And of receiving written information on paper, instead of orally, Lord Judge warned: "We all know of cases which on paper look very strong against the defendant which, as the trial unfolds through oral testimony and cross examination, demonstrate that the entire prosecution case was structured on paper and is no stronger than paper."