This is the dramatic moment a group of far-right Trump supporters tried to arrest Sadiq Khan while quoting the Magna Carta.
The men stormed the Fabian Society conference in London moments after the mayor took to the stage and accused him of 'subverting the English constitution'.
Mr Khan's speech had to be suspended for several minutes as the demonstrators from a group called the White Pendragons were escorted out by police.
The chaos appeared to have been sparked by Mr Khan's comments about the US President's decision to cancel his UK visit.
Mr Trump claimed he pulled out of opening the new American embassy in London because he disagreed with the decision to sell off the old building for 'peanuts'.
The men stormed the Fabian Society conference in London moments after the mayor took to the stage and accused him of 'subverting the English constitution'
But Mr Khan said it was clear that Mr Trump had 'got the message that many Londoners' did not want him here.
As the London Mayor started to speak at today's event, the protesters stood up and shouted that they were making a 'citizen's arrest'.Labour MP Wes Streeting: The single biggest barrier to a soft Brexit is my party
Amid the chaos of Sadiq Khan's speech at the Fabian Society conference today, calls were also made by Labour backbenchers for Jeremy Corbyn to harden his party's Brexit policy.
Ilford North MP, Wes Streeting claimed that his party leader's Brexit policy is now the single biggest barrier to Britain remaining in the EU single market.
Streeting is one of number of other backbenchers saying he would back continued membership of the single market and the customs union.
In a speech to the Fabian Society today, Streeting said: 'On the UK’s future relationship with the European Union – the single biggest issue facing our country in a generation – we find ourselves in the terrible position where it is the Labour party that currently stands as the single biggest barrier to the UK’s membership of the single market and customs union.
'The burden of responsibility lies with us, because if the Labour Party announced tomorrow that we would keep Britain in the single market it would be a game-changing moment in British politics.
'With Labour’s support, the policy would command a majority in the House of Commons and a majority in the country.
'Brexit hasn't been an easy issue for our party since the referendum. We couldn't wish for anyone better than Keir Starmer to forensically pick apart that idle chancer David Davis – and even if we had the most pro-European of Labour leaders they would be confronting the same political calculations facing Jeremy Corbyn.
'The country is looking for leadership. It’s time the Labour Party provided it. So let's answer the call of a majority of Labour members, a majority of Labour voters and a majority of the British people by using our parliamentary muscle to keep Britain in the single market. Labour’s leadership must surely recognise that there is no socialism in going it alone.'
The men - who got into the event by buying tickets - also vowed to take the panel's chair Kate Green MP into custody as well as Sir Keir Starmer and general secretary Andrew Harrop.
They then told guards that they were attempting to arrest the politicians under 'common law jurisdiction' and the Magna Carta - the 13th-century document that is often regarded as the foundation of the modern legal system.
The men - who got into the event by buying tickets - also vowed to take the panel's chair Kate Green MP into custody as well as Sir Keir Starmer and general secretary Andrew Harrop
As fellow demonstrators waved anti-EU signs and American flags, one of the group yelled: 'Ladies and gentleman, we are here today to make a peaceful, non-violent citizens arrest of those being named'
As fellow demonstrators waved anti-EU signs and American flags, one of the group yelled: 'Ladies and gentleman, we are here today to make a peaceful, non-violent citizens 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.'
One of the protesters was English Defence League member Dave Russell, a self-described talk show host from London. He live-streamed the protest to his Facebook account racking up thousands of views.
Amid heckles and chants of 'scum', chair Kate Green MP told the audience: 'I can assure you nobody is leaving and when the police arrive you will be able to talk to them.
'Those who would like to speak to the police can do so when they arrive. those who want to have a discussion about the future Labour government can stay in this hall.'
The group told guards that they were attempting to arrest the politicians under 'common law jurisdiction' and the Magna Carta
One of the protesters named Dave Russell, pictured, a self-described talk show host from London, live-streamed the protest to his Facebook account racking up thousands of views
When Mr Khan resumed his speech after the protesters were escorted from the venue by police, he took a dig at the American president who recently described himself as a 'very stable genius'.
Mr Khan told delegates: 'It is a pleasure to be here even though we were distracted by the actions of what some would call very stable geniuses.'
The mayor and US president have clashed publicly a number of times over issues like counter terrorism and Mr Trump's proposed state visit to the UK.
The mayor also tried to make light of the protest with a reference 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.'