Rosalind Wright, the director of the Serious Fraud Office (SFO), has attacked defence lawyers by suggesting that they make fraud trials last as long as possible in the hope of obtaining an acquittal from a confused jury.

Speaking at the 16th International Symposium on Economic Crime in Cambridge last week, Wright said: "In many cases one is driven to the conclusion that it is in the defence's interests to prolong the trial process for as long as possibleS in keeping the issues blurred and unclear, the jury may not be able to see the wood for the trees and will give the defendant the benefit of the doubt."

And she added: "Preparatory hearings, designed to streamline the issues and reach accord on what could be agreed by both sides before trial, are not working as well as they should. Defence counsel are reluctant to concede points pre-trial."

In her speech, Wright also said she would replace juries with a judge sitting with specially-qualified lay members.

She said: "You wouldn't have to tell them what a share option was, what reinsurance was all about – or if you did they'd understand pretty quickly."

However, she said, whether a case should go to a jury or such a panel would be up to the judge following representations from both prosecution and defence, and the judge's decision would be subject to appeal.

In February, the Home Office issued a consultation paper proposing to dispense with jury trials in complex fraud trials.

In its response to the paper, the Criminal Bar Association delivered a strong defence of the jury system, claiming its abolition would deprive defendants of a long-held constitutional right.