The announcement came just one week before the Hicks case was due to be heard in the Supreme Court of New South Wales.

Steven Glass, a partner at Gilbert + Tobin which has been acting for Hicks, said: “We believe the evidence we submitted demonstrated David’s plea agreement was made under duress – an admission extracted under extremely harsh conditions at Guantanamo. We’re pleased the CDPP has withdrawn the case”.

Hicks, an Adelaide-born man, was captured by the Northern Alliance in Afghanistan in 2001 and handed to US forces, spent almost six years detained at Guantanamo Bay before he was finally released in 2007.

Proceedings were commenced against Hicks in July last year, with the CDPP arguing that under the Proceeds of Crimes Act 2002 (Cth) Hicks should be required to forfeit the profits of his book.

The CDPP said it would rely on Hicks’ agreement in 2007 to plead guilty to charges that he had provided “material support for terrorism”. It argued that the guilty plea meant that he was prohibited from earning profits from his book.

The defence team argued that the CDPP should not be able to rely on the plea agreement, because the conditions at Guantanamo amounted to duress. 

According to Gilbert + Tobin, the CDPP decided to abandon the case just weeks after the Hicks defence team provided evidence to the CDPP of the oppressive circumstances in which Hicks had agreed to plead guilty.

Michael Mori and Joshua Dratel, the two American lawyers who represented Hicks in Guantanamo and had advised him to plead guilty as a way to be sent home, had both given strong evidence supporting his case.

The law firm said Hicks’ legal team was to argue that the offence of providing “material support for terrorism”, which was made law in the United States in 2006, was not an offence either in the US or Australia in 2001 when the alleged conduct occurred. They say that the Proceeds of Crimes Act does not permit the confiscation of proceeds of retrospective foreign offences.