Mr Khan’s speech at a Fabian Society new year conference was suspended for several minutes due to the incident.
Police eventually managed to lead the demonstrators, believed to be from the White Pendragons, out of the venue.
The protestors held up United States flags and called for Mr Khan to be arrested, saying power had gone to his head
A spokeswoman for the Fabian Society confirmed to Express.co.uk the speech had been marred by what she described as “far right” protestors.
In video footage of the incident one man could be heard saying: “Ladies and gentlemen, we’re here today to make a non-violent, peaceful citizen’s arrest.”
Audience members started to heckle and slow-clap, during which security appeared.
The protest was apparently against comments made by the Mayor of London about Mr Trump’s plans to cancel his trip to the UK.
The group entered the conference moments before Mr Khan was due to make his keynote speech.
Their attempts to eject the protestors for the disruption were initially met with aversion from the protesters, one of whom could be heard saying: “We stand under Common Law jurisdiction.
“If you touch us, you’ll be done for common assault. Please stand back, do not touch us.
“We’re not leaving, we’ve paid for a ticket.”
He then accused the Fabian Society of “subverting” the constitution.
The mayor appeared to read a newspaper as the group were led out of the hall to cheers from attendees of the Fabian Society.
When he resumed his speech Mr Khan tried to make light of the incident referring to Prime Minister Theresa May’s Tory conference speech which was interrupted by a prankster, saying: “On the plus side I wasn’t served with a P45.”
And in a dig at the US president after Mr Trump described himself as a “very stable genius”, Mr Khan said: “It is a pleasure to be here even though we were distracted by the actions of what some would call very stable geniuses.”
It comes a day after the London Mayor, a long-term opponent of Mr Trump, said the US President had…