Denis O’Brien has been accused of breaching a high court order to preserve the integrity of a USB memory stick that is central to a defamation and conspiracy case he has taken against a public relations firm.

Lawyers for Red Flag Consultants yesterday accused Ireland’s richest man of failing to comply with Judge Colm Mac Eochaidh’s order that the USB stick containing all the evidence in the case be delivered “forthwith” to Mr O’Brien’s solicitors and not be interfered with.

Mr O’Brien’s counsel described the allegation as “outrageous”.

The billionaire businessman has claimed that the memory stick was delivered anonymously to his office on Grand Canal Quay on October 8. He said that he gave it to his solicitor, who then passed it on to