The top prosecutor in England and Wales has refused to consent to the private prosecution of terror suspects Babar Ahmad and Syed Ahsan.
Keir Starmer QC, the Director of Public Prosecutions, said the documents provided by British businessman Karl Watkin were "very short, lack any meaningful detail and do not provide any real support for a prosecution".
Mr Watkin, a campaigner against the UK's extradition arrangements with the United States, made the attempt to bring legal proceedings against the pair in the UK to avoid "outsourcing the country's criminal justice system" to the US.
Mr Starmer went on: "The underlying evidence in support of these alleged offences is in the possession of the USA.
"In the circumstances, I have refused to give my consent to Mr Watkin to bring a private prosecution against Mr Ahmad and Mr Ahsan for offences under the Terrorism Act 2000."
Mr Ahmad has been in jail without trial since 2004 while fighting extradition and has pleaded to be charged and tried in Britain.
The pair are accused of being involved in a website which encouraged terrorism and which, while operated from London, was hosted in the US.
Neither has been charged with an offence in the UK relating to the website Azzam.com, even though the investigation by US authorities includes evidence seized by the Metropolitan Police. The CPS has refused to prosecute the men.