Tens of thousands of people took part in a "Unite the Kingdom" rally in London, England, on Saturday, where demonstrators also honored Charlie Kirk with some holding pictures and banners of the late conservative activist.
Organizers played a heartwarming tribute video to Kirk that included a viral clip of him giving life advice to a 13-year-old girl at a Turning Point USA event.
The rally was organized by activist Tommy Robinson, who said the video was shown to thank and "honor the life of one of our generation's greatest." Elon Musk also appeared via video link and condemned the left as "the party of murder" following Kirk's death.
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Robinson billed the march as a demonstration for free speech, saying it was also held in defense of British heritage and culture.
"A man who inspired a generation of young men based on courage and based on faith," Robinson told the cheering crowd, which also sang Kirk's name.
"In honor of Charlie Kirk and in honor of freedom on the 13th we march," Robinson wrote in a social media post earlier in the week.
One demonstrator carried a sign reading, "Freedom of speech is dead. RIP Charlie Kirk," according to The Associated Press.
Aerial shots showed streams of demonstrators carrying the red and white St. George's Cross flag of England and the Union Jack. Many chanted, "We want our country back!"
Police estimated the crowd at about 110,000 people, while organizers claimed the figure was in the "millions." A rival protest drew about 5,000 marchers.
Musk condemned the killing of Kirk, who was fatally shot on Wednesday at Utah Valley University. Tyler Robinson, 22, has been arrested for the crime.
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"You see how much violence there is on the left, with our friend Charlie Kirk getting murdered in cold blood this week, and people on the left celebrating it openly," Musk said.
Robinson praised Musk for purchasing Twitter and lifting bans on right-wing commentators, saying Saturday's event would not have been possible without him.
He added that the British public were "telling the world they're ready to fight back," linking that directly to Musk giving them a platform.
Robinson told the crowd in a hoarse voice that migrants now had more rights in court than the "British public, the people that built this nation."
The marches come as the U.K. is riven by debate over migrants crossing the English Channel in overcrowded boats to arrive without authorization.
Musk warned of the dangers of stifling free speech and said the U.K. was at a critical point in its history.
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"You can't get to the truth without freedom of speech, without active debate… the essence of democracy is a government for the people, by the people."
He added that the U.K. was in danger of losing its identity due to mass migration, accusing the BBC of being "complicit in the destruction of Britain." He also claimed mass migration was being used to import new voters.
"I see a rapidly increasing erosion of Britain with massive, uncontrolled migration and a government that has failed in its duty to protect its citizens."
"Britain is at a fork in the road - to darkness or greatness - and that will be decided only in a matter of years."
Fox News' Greg Norman and The Associated Press contributed to this report.
