Once again the spotlight has focused on charges of serious fraud and the capacity of the criminal justice system to deal with them.

Since it was set up in 1988, the Serious Fraud Office (SFO) has brought to trial 150 of the most serious cases.

Staffed by experienced lawyers and accountants, the SFO has strong powers of investigation, working in close co-operation with the police in multi-disciplinary teams.

It calls heavily upon the private sector both from the accountancy profession and the independent Bar and, as a result, fewer serious cases do not result in prosecution.However, a small number of very large SFO cases -- perhaps no more than half a dozen -- have thrown up problems that have particularly tested the new regime.The Court of Appeal's decision to quash the guilty verdicts in the Blue Arrow case has arguably been the most influential event in the SFO's history.

The court encouraged 'the robust and early use' of the power of severance of the indictment in order to secure a manageable and fair trial before a jury.

The court also said that trial judges would seldom have occasion to sever if the prosecuting authorities framed indictments that had due regard to the limitations of jury trial.In planning its investigations and prosecutions, these directions have been at the forefront of the SFO's thinking.

The office has not overloaded indictments but has endeavoured to reflect in the charges sufficient criminality to enable juries to convict with confidence.There will inevitably be a few cases, which have several principal defendants, that are so complex that it is impossible to reduce them to a point where the whole indictment against all defendants can be tried in a single trial.

In these cases -- and Maxwell was one of them -- the judg e must sever the indictment, splitting it up to be dealt with in two or even three trials.

The consequence, however, is that the first and any subsequent trials will proceed on only part of the available evidence, with only some of the defendants before the court in each case.

A single jury will never see the full weight of the case against all.Last week's ruling in the Maxwell case does not necessarily mean that, after an acquittal, severed counts cannot be tried in a subsequent trial, but the judge made it clear that it should be 'unusual' for a second trial to take place.

The position now is that in the most complex cases of alleged fraud, the indictment, already reduced to the bare minimum as directed in Blue Arrow, will be split up to produce a series of manageable trials, but it is very unlikely that a second trial will ever take place.

That means the full extent of the alleged criminality is unlikely ever to come before a court, nor will all the defendants.

The system is thereby emasculated.We must now ask whether the Court of Appeal's directions in Blue Arrow are still workable.

If it is unreasonably burdensome for a jury of 12 ordinary people to be asked to try the whole case, the question arises of what sort of alternative tribunal would be suitable.

The Roskill committee's solution was to have a judge sitting with two suitably experienced lay members.It is not a question of whether juries can understand these cases.

The SFO and leading counsel who represent the office in court have well developed techniques for presenting and explaining complex evidence to non-experts.

Still less is it a question of the decisions of juries not being accepted by the authorities, as was suggested in last week's judgment.

The question is whether it is reasonable to ask an ordinary jury to sit for as long as it inevitably takes in the most complex cases to hear the entire case and, at the end of this process, deliver a verdict.

The Maxwell case has serious implications for the prosecution of the largest and most complex criminal cases.

A solution to this problem is urgently required.