This one is extremely underreported. I only found that one report in English and another one in german (see two links below). Would be good to share it, so that it at least gets a bit of traction:
UK: 370 world leaders, politicians, diplomats, and lawyers pen open letter calling for Assange's release | Video Ruptly
deutsch.rt.com
UK: 370 world leaders, politicians, diplomats, and lawyers pen open letter calling for Assange's release | Video Ruptly

190 Staats- und Regierungschefs, Diplomaten und Anwälte fordern Freiheit für Assange (Video)
Zahlreiche Experten, darunter prominente Politiker und Anwälte, fordern von der britischen Regierung den Freispruch für Julian Assange. Sie setzten sich nicht nur für die Freiheit des Journalisten ein, sondern machen sich auch grundsätzlich für politische Freiheiten stark, die sie nun bedroht sehen.
www.ruptly.tv/en/videos/20200921-056-UK--370-world-leaders--politicians--diplomats--and-lawyers-pen-open-letter-calling-for-Assange-s-release said:UK: 370 world leaders, politicians, diplomats, and lawyers pen open letter calling for Assange's release
Some 370 world leaders, politicians, lawyers and academics called on the release of WikiLeaks founder Julian Assange from prison signing an open letter, according to Lawyers for Assange member and legal researcher Polona Florijancic, London, Monday.
The open letter is addressed to UK Prime Minister Boris Johnson and other government ministers and includes signatories ranging from Argentine President Alberto Fernandez to former Brazilian Presidents Dilma Rousseff and Luiz Inacio Lula da Silva.
"On the one hand we have a journalist who has exposed incredible war crimes and torture and corruption, on the other hand we have the embarrassed superpower that wants to prosecute him," said Polona Florijancic, an independent legal researcher and member of Lawyers for Assange. "Currently, 190 lawyers and legal academics, judges and professors have signed this letter, including 19 lawyers' associations, three of them with consultative status at the United Nations."
"The prominent signatories from the politicians now are the heads of state. And here I would like to mention (former Spanish Prime Minister Jose Luis) Zapatero who is a lawyer himself," Florijancic continued. "So, you can see again someone who knows exactly what he is signing." Assange has been behind bars in Belmarsh Prison since he was dragged out of the Ecuadorian Embassy in April 2019. He faces multiple charges in the US related to espionage. His trial on possible US extradition started on September 7. [...]