The need for trials of fraud and other complex crimes to be brought back to an "acceptable and proper duration" has been emphasised by the Lord Chief Justice.
Lord Woolf said there was a "broad consensus that the length of fraud and trials of other complex crimes must be controlled".
This was in order to enable a jury to "retain and assess the evidence which they have heard".
He said: "If the trial is so long that the jury cannot do this, then the trial is not fair either to the prosecution or the defence."
Issuing a protocol on the control and management of heavy fraud and other complex criminal cases at the Royal Courts of Justice in London, Lord Woolf said it was also necessary to control such cases "to make proper use of limited public resources".
He said: "There is also a consensus that no trial should be permitted to exceed a given period, save in exceptional circumstances; some favour three months, others six.
"Whatever view is taken, it is essential that the current length of trials is brought back to an acceptable and proper duration."
He said the best handling technique for a long case was continuous management by an experienced judge nominated for the purpose.
Lord Woolf stressed that "thorough, well-prepared and extended case management hearings will save court time and costs overall".
A heavy fraud or other complex trial has the potential to lose direction and focus, he said, which was a "disaster" for three reasons.
* The jury will lose track of the evidence, "thereby prejudicing both prosecution and defence"
* The burden on the defendants, the judge and "indeed all involved will become intolerable".
* Scarce public resources are wasted: "Other prosecutions are delayed or - worse - may never happen. Fraud which is detected but not prosecuted, for resource reasons, undermines confidence.