The first official UK Pride march took place in July 1972, following the 1969 Stonewall uprising in New York.
Rebecca Paisis, interim chief executive for the event, spoke about the power of collective action.
"Our movement has always been built on many voices becoming one united front – from the people who marched in 1972 to those joining us for the first time this year.
That's where our power lies," she said.
Paisis added that coming together is key to overcoming adversity.
"As LGBTQ+ people, we've never been strangers to adversity, but neither are we strangers to collective action," she said.
>>> William Shatner Open to Returning as Captain Kirk at 95
The London event has faced criticism from some activists over corporate sponsorship ties to the arms trade and the war in Gaza since 2024.
