Police are appealing for witnesses to come forward after the “senseless attack” on journalist Owen Jones.
The Guardian columnist was out celebrating his birthday with friends when set upon in what he described as a “blatant premeditated assault”.
The Metropolitan Police said detectives are investigating whether a hate crime had been committed after the assault in Islington, north London.
The attack happened at around 2am on Saturday (August 17) outside a pub on Pentonville Road.
Jones was assaulted by four male suspects, and his friends were also attacked as they attempted to intervene.
Detective Sergeant Scott Barefoot of Islington CID said: “This was a completely senseless attack on a man simply enjoying a night out with friends.
“We are looking into the circumstances of this incident, including if it was a hate crime. Although there were no serious injuries, the effects of becoming a victim of such an attack can continue when any injuries have healed.
“If you were in in the area, if you saw a group of males in the Pentonville Road area at the time or have footage of them, please come forward. You can come forward anonymously if you prefer, but please do make the call.”
Taking to Twitter in the aftermath of the incident, Jones indicated he thought the attack was motivated by far-right ideology.
He added: “Given the far-right attacks I’ve had in the streets, and generally escalating far-right attacks I’ve had, I’m in no doubt what this is.
“They spotted me in the pub, waited for us to leave, and then launched their attack when we were away from the pub.
“It was planned, not a random attack.”
The left-wing activist described the attack on social media.
He said: “Six of us left the pub at 3am and were saying our goodbyes 30 metres away, then a group of three or four men left the pub, made a beeline for me, kicked me in the back, threw me on the ground, slamming my head, and kicked me in the skull.
“My friends were punched trying to defend me.”
Labour leader Jeremy Corbyn sent a message of “solidarity” to Jones.
Corbyn said: “Owen believes it was politically motivated, and we know the far right is on the march in our country.
“An attack on a journalist is an attack on free speech and our fundamental values.”
Guardian editor Katherine Viner has condemned the attack.
She said on Saturday evening: “At the Guardian we deplore the outrageous attack on Owen Jones that took place late last night.
“Violent assaults on journalists or activists have no place in a democratic society.”