Pride in London organisers have apologised after anti-trans protesters “forced their way to the front of the parade”.
Members of lesbian and feminist group Get The L Out demanded to march behind the rainbow flag, which marks the start of the event, organisers said.
The group believes lesbian rights are attacked by the trans movement.
Pride said their behaviour on Saturday was “shocking and disgusting”.
It said they could not forcibly remove the small group as their protest was not a criminal offence, adding “we are sorry”.
A statement said: “The protest group showed a level of bigotry, ignorance and hate that is unacceptable.
“We reject what this group stands for. They do not share our values, which are about inclusion and respect and support for the most marginalised parts of our community.
“We are proud of our trans volunteers, proud of the trans groups that are in our parade, proud of our trans speakers at events and proud of the trans people who take part in our campaigns and proud of those who cheered even louder for them yesterday.”
The parade, which coincided with England’s World Cup quarter-final in Russia, included about 30,000 people from 472 organisations.
Up to one million other people are thought to have lined the streets to watch the event.