(Express) -- 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.

The protestors not only threatened to make an citizen’s arrest of the London mayor but also Sir Keir Starmer, the shadow Brexit secretary and the panel’s chair Kate Green MP as well as general secretary Andrew Harrop.

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 of those being named.

“They are Sadiq Khan, Keir Starmer, Kate Green MP and Andrew Harrop.

“We stand under common law jurisdiction. If you touch us you will be done for common assault. Do not touch us. We're not leaving, I've paid for a ticket.”

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.

The mayor appeared to read a newspaper as the group were led out of the hall to cheers from attendees of the Fabian Society.

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 “got the message” that Londoners opposed his views and policies as he cancelled a planned visit to the capital.

(Photo: A protestor holds up an anti-EU banner during Sadiq Khan's speech to the Fabian Society, Reuters)