Key speakers at the rally included UK shadow chancellor John McDonnell, Julian Assange defence team member and barrister Jennifer Robinson, Wikileaks editor-in-chief Kristinn Hrafnsson, UN special rapporteur on torture Nils Melzer, UK shadow justice minister Richard Burgon and New Left Review editorial committee member and renowned activist, Tariq Ali.
Groups supporting the rally included the Stop the War Coalition, Socialist Equality Party, Campaign to Defend Julian Assange, Julian Assange Defence Campaign, among others.
Members of the panel spoke out against the whistleblower's arbitrary detention at Belmarsh Prison, where the activist could receive up to 175 years in a US federal prison following an extradition request from Washington.
The following are highlights from speeches delivered at the rally.
Kristinn Hrafnsson, Renowned Journalist and Editor-in-Chief for Wikileaks
Discussing the future of journalism amid the ongoing Assange case, which could set dangerous precedents for future journalists:
"We're dealing with political corruption [and] persecution. This has nothing to do with justice. But we need to fight and tear down this wall around Julian and free him.
I remember shortly after he was arrested, we asked him what to relay to the journalists outside. He replied: "Tell them, it's not about me, it's about them!"
Jennifer Robinson, Member of Julian Assange's Defence Team and Barrister for Doughty Street Chambers
Speaking on the impetus to defend Julian Assange's work, which has led Wikileaks to international acclaim:
"I always think it's important to remember what these publications were and their significance. The publications for which he now sits in a high-security prison, over in Belmarsh.
[Revelations on] collateral murder. Evidence of war crimes. The killing of journalists in a conflict in which they posed no risks. The Afghan and Iraq war logs. Evidence of torture. Mistreatment of political detainees. The killing of civilians far beyond what the US government was reporting on its own.
Cablegate, diplomatic cables which revealed the true nature of US imperialism. The fact that the United States was ordering the spying on UN diplomats. Corruption, torture, human rights abuses the world over.
For that reason, we've been saying for years that the media needed to stand with WikiLeaks to defend against the precedent being set, because it would have a chilling impact on investigative journalism the world over."
Nils Melzer, UN Special Rapporteur on Torture and Swiss Academic
Speaking in metaphor on the focus of the media narrative surrounding Julian Assange and the significance of his work with Wikileaks:
"Julian Assange has taken the flashlight in that dark room and pointed it at the elephant. The elphant of war crimes, of misconduct, under the colour of law [...] of serious violations of human rights.
But despite his spotlight, the elephant, as a deer in the headlights, was frozen for a couple of moments, and for a couple of weeks, everyone was discussing these revelations.
But then the elephant snatched the spotlight, turned it over, and pointed it at Julian Assange. The room became dark, and the only thing we could see was Julian in the corner with the spotlight on him.
And now everyone discussed his character, his private habits, does he wear shorts or long pants during his video conferences, was he skateboarding at the embassy, what was he feeding his cat, was he smearing things on the embassy walls... absolutely trivial things compared to the revelations he made.
Who has the spotlight? It's certainly the governments and the media. The media are supposed to serve and inform us to empower us, not just to entertain us.
We won't look at the elephant in the dark. And this is what this is all about."
Richard Burgon, Shadow Justice Minister for The UK Labour Party
Speaking on the role of the Conservative UK government, which signed off on the US request to extradite Julian Assange to Washington:
"Just imagine how poorer our understanding of the barbarity of the Vietnam War would have been had those who exposed US atrocities had been subjected to prosecution for doing so.
Are we really going to hand over someone to spend 175 years - the rest of their life - in prison for exposing killings and abuses in Iraq and Afghanistan, including the killing of journalists?
It's wrong that the Conservative government signed the extradition warrant to the United States. It not only appears as yet another example of kowtowing to US foreign policy, but it seems to me to be a complete failure to respect the basic principles of journalistic freedoms.
This issue goes way beyond the case of Wikileaks. It's a clear attack on all of those who wish to expose abuses of state power, and an attack on journalists who report on them."
John McDonnell, Shadow Chancellor for The UK Labour Party
Discussing the need to protect journalists and whistleblowers exposing government crimes and corruption:
"The reason why I'm here is in an act of solidarity. I'm a member of parliament, and the role of an MP is to supposedly stand up for democracy and democratic rights of individuals, as well as protect the rights of those democracies from threats, wherever those threats come.
So, it's a huge breakthrough, and the State in its usual role try to close down access to individuals like us and civil society towards that truth, and that's what this is about. It's about the individual, Julian Assange, but it's also the principle and the protection of democracy, but also the throw a light on the iniquity perpetrated in our name."
John Rees, National Officer for Stop the War Coalition
Urging attendees to campain for Wikileaks, Julian Assange, and the strength of such campaigns in successfully freeing the Australian publisher:
"The one thing that has improved Julian Assange's conditions in Belmarsh, which got him out of solitary confinement, was campaigning.
There was campaigning from ordinary activists and the legal team, but most impressively, it was three petitions by Belmarsh prisoners themselves demanding that his circumstances be changed because they were unjust and unfair. If they can do it, in the most difficult circumstances imaginable, you and I with much greater freedom can do it as well.
This legal process is corrupt. [Assange] will never be in front of a jury in this country. He will only be tried by a judge, and when he gets to the United States, he will only be in front of a jury who are to be selected locally in Alexandria, Virginia, where 80 percent of jurors are employees of the Pentagon, the National Security Agency or the Central Intelligence Agency. He will go to no jury to to bent jury, and you will never hear that voice again."
Tariq Ali, Member of the Editorial Committee of the New Left Review, Activist, and Journalist
Detailling the information in the Wikileaks revelations, including major war crimes from the US and UK as well as the need for states to silence dissenters:
"Why, if we know the scale of massacres that took place? We know what happened in Fallujah in Iraq, when they were shooting wounded Iraqi prisoners in the head, saying "that's what you do to dying animals", according to a NYT report.
No prosecutions at all by any international body. Why? Because they're supposedly our wars, and our wars are good wars, and killing the enemy is part of our patriotic duty.
In any system which was genuinely impartial... I mean, why wouldn't Bush, Cheney and Blair an international court?
This is the context to understand what is happening to WikiLeaks, to Julian Assange, and why they're so determined to crush dissent. It's not simply Wikileaks, but other journalists are under fire. "Don't do it again", they say.
Who will prosecute them? It's an act of state terrorism, openly admitted. They say they have the right to do it. Why do they have the right to do it? We're the imperial power, and imperial powers can carry out atrocities as the European empire has showed over centuries."