There was no investigation by gardaí into the shredding of documents by a state investigator in the case of Sean FitzPatrick, Dublin Circuit Criminal Court has been told.

Mr FitzPatrick, the former Chairman of Anglo Irish Bank, has pleaded not guilty to misleading the bank's auditors and furnishing false information about loans to him and people connected with him.

The main investigator from the Office of the Director of Corporate Enforcement has admitted shredding documents relevant to the case, in what he described as a "calamitous error".

The jury was shown CCTV footage of Kevin O'Connell from the ODCE leaving the shredding room in the office, on 1 May 2015, swinging an empty tray in his hand.

He has already admitted making a dreadful mistake, by shredding documents relevant to the investigation "in a time of enormous stress".

He agreed under cross examination by lawyers for Sean FitzPatrick that it was a criminal offence to destroy documents relevant to an investigation.

But, he agreed, there had been no garda investigation at all into what had happened.

Mr O'Connell said that when he told his boss, Director of Corporate Enforcement, Ian Drennan, what he had done, he did so knowing it could have led to several very serious outcomes for him.

But he said there was no garda investigation and no disciplinary action was taken against him.

He said during this trial, in October last year, he became aware that there was more risk of him being prosecuted than he had previously thought.

He had intended to "plead the 5th" or exercise his right not to answer certain questions in case he incriminated himself.

The court heard Mr O'Connell's solicitor wrote to the DPP. And the DPP gave an undertaking that no evidence given by him in this trial or any further trial of Sean FitzPatrick would be used in evidence in any criminal proceedings against him.

Lawyers for Mr FitzPatrick said Mr O'Connell had effectively been given immunity from prosecution by the failure of the gardaí to carry out their duty to investigate the matter.

Mr O'Connell said he would not accept he had immunity but accepted he had the benefit of the DPP's undertaking.

His cross examination is continuing.