Six people have been arrested as a St George’s Day event was held in Whitehall.

Videos posted on social media show disorder breaking out and people being detained by officers at the event, which was attended by Tommy Robinson, who was one of the speakers.

The Metropolitan Police posted on X, formerly Twitter, earlier on Tuesday to say they expected “far-right groups and groups linked to football clubs” to attend.

Four arrests were made outside a pub in Whitehall – one on suspicion of assault and three on suspicion of assaulting an emergency worker, the Metropolitan Police said.

An image was shared on X by the force which shows dozens of officers and multiple police vans near a crowd on a pavement.

Earlier, a man was arrested on suspicion of animal cruelty after “a police horse was targeted on Whitehall”, the force added.

And another man was arrested on suspicion of being drunk and disorderly.

Before the event began on Tuesday afternoon, mounted officers on horses had to intervene after disorder broke out.

A group broke through a police cordon that was formed to stop people who had moved past an area in Richmond Terrace, which was allocated for the event, the Metropolitan Police said.

The Metropolitan Police later shared a video on X that appears to show officers forming a cordon but a group, some waving flags and others wearing St George’s flags, pushing past it before two mounted officers on horses intervene.

The force posted the video just after 2pm on Tuesday along with the message: “The event is not due to start for an hour and regrettably officers are already dealing with disorder.

“There is an area allocated for this event in Richmond Terrace. This group went past it and continued up Whitehall.

“When officers formed a cordon and asked the group to turn round, they reacted by violently forcing their way through. Mounted officers intervened with horses to restore the cordon.”

Whitehall had to close to traffic while police officers dealt with the incident.

Another earlier post from police said a number of people had been seen in the area wearing masks and a Section 60AA order is in force in the boroughs of Lambeth and Westminster “giving officers the power to require the removal of face coverings”.

A Section 60 order, giving officers additional search powers, is also in force in the same area to prevent crime and disorder, the force added.

After the incident, a group gathered on Whitehall opposite Downing Street where there was also a large police presence.

Attendees waved St George’s Cross flags and listened to speeches, including by Mr Robinson, who was cleared of breaching a dispersal order at court earlier on Tuesday.