"There is plenty of evidence showing that Assange is a victim of judicial persecution and that he is not getting a fair extradition trial here in the UK, and certainly will not have a fair trial in the US", the former diplomat told Sputnik in a phone interview.
According to Narvaez, the judicial persecution against the Australian journalist began even before he was arrested on 11 April 2019, at the Ecuadorian Embassy in London, where he enjoyed political asylum for seven years to avoid being sent to Sweden until Ecuador's current government handed him over to the UK police last year.
After being sentenced to 50 weeks in jail for jumping bail in a hearing that lasted less than 15 minutes, Assange was sent to Belmarsh maximum-security prison in east London, where visits by relatives and lawyers are normally restricted.
Narvaez said that since the coronavirus pandemic struck, the WikiLeaks founder has seen his solitary confinement conditions worsened. The whistleblower has not been allowed to see his partner and sons, nor meet his lawyers in person, due to social distance restrictions.
It even took months for the prison authorities to give him a pair of reading glasses and a radio receiver he had requested, Narvaez commented.
He also recalled that when the extradition trial began in February in a London court, Assange was not allowed to sit with his lawyers, and was instead forced to watch the process from behind high walls made of glass panel.
"The British judicial system has been particularly hard on Assange, and not just me, but many international lawyers think that he is not being granted the right to a fair trial", Narvaez stressed.
Asked about the new "superseding indictment" against the WikiLeaks founder that the US prosecution made public even before formally presenting it to the British court dealing with the extradition request, Narvaez called it a "publicity stunt".
"They [the US prosecutors] know they have nothing new. They just want to attract public attention", he claimed.
The US federal government charged Assange with 18 criminal charges related to endangering US national security by conspiring to obtain and disclose classified information.
If the UK court consents to his extradition in the trial due to resume on September 7, Assange could be sentenced to 175 years behind bars.
At the last administrative hearing held on 27 July, Assange appeared by video link from prison for the first time in months.