The report into the collapse of the £25m Jubilee Line fraud trial in March has blamed the lack of a "clear strategy" for dealing with such cases.
All six defendants in the £25m case were acquitted
Six men were accused of fraud and corruption over contracts awarded for the Tube extension in the mid-1990s.
The case failed after almost two years in court, partly due to jury problems.
Attorney General Lord Goldsmith said it "illustrates a good deal about the challenges of presenting long and complex cases in front of a jury".
The government has already passed a law allowing complex fraud trials to be heard without a jury, but has postponed introducing it.
The inquiry into the collapse of the case was ordered by Lord Goldsmith.
Chief Inspector of the Crown Prosecution Service (CPS) Stephen Wooler said the case was so complex it was not possible to prove whether juries should be dropped in similar cases.
Lord Goldsmith called for an inquiry into the case
Lord Goldsmith said he took "a different view" but told the House of Lords he was very clear that individual jurors were not to blame for the collapse of the fraud case.
He said: "I accept the report's conclusion that fraud work within the CPS has not always been recognised as requiring a degree of dedicated resource and expertise.
"That is now being rectified with the establishment of a separate and specialist fraud prosecution division within CPS London, a move welcomed by the report."
He said the use of case management panels since September 2005, to advise lawyers working on fraud cases, had "proved their worth".
They had strengthened the presentation of cases, the identification of any potential weaknesses and in some cases shortened the predicted trial lengths, he said.
The inquiry said jurors in such complex fraud cases should be given better support to help reduce disruption to their personal and family lives.
The 240-page report criticised prosecutors for including a charge of conspiracy to defraud which it says "lacked precision" and considerably slowed down the trial.
It said jurors felt "trapped" because the trial had gone on twice as long as was initially thought.
'Breakdown in supervision'
Mr Wooler criticised the CPS's decision to include one of the counts in the indictment, saying the conspiracy to defraud charge "lacked precision", adding further complexities to the trial and slowing down legal proceedings.
"Had it not been included the prosecution case would have been completed during October 2003 rather than August 2004," the report added.
It said other factors, such as the illness of one of the defendants were beyond anyone's control.
But the review said there was a "breakdown in the supervision" of major cases by senior Crown Prosecution Service managers. It said the CPS "lacked a clear strategy for the handling of heavy fraud work."
The report said jurors should be given clear information about what is expected of them and kept fully informed about the progress of a trial.