The Guardian columnist and activist Owen Jones has been physically assaulted in London while celebrating his 35th birthday with friends.

In an attack he called “a blatant premeditated assault”, Jones said he was kicked, punched and thrown to the ground by a group of men in the early hours of Saturday morning.

He said that he and his friends went to a pub and left at 3am. “We were about 30 metres away, saying goodbye to each other, when four men charged directly towards me: one of them karate kicked my back, threw me to the ground, started kicking me in the head and back, while my friends tried to drag them off, and were punched trying to defend me.

“It was clearly a premeditated attack and I was their target. They all attacked me and only assaulted my friends when they tried to defend me.

“In the past year I’ve been repeatedly targeted in the street by far right activists, including attempts to use physical assault, and homophobic abuse. I’ve had a far-right activist taking pictures of me, and posting threatening messages and a video.

“Because of this, and escalating threats of violence and death, I’ve had the police involved. My friends felt it was a matter of time until this happened. Give the context, it seems unthinkable that I was singled out for anything other than a politically motived premeditated attack.”

He blamed the attack on “the rise of an emboldened far right, which is increasingly violent, and targeting minorities and people on the left”.

He added: “They are being radicalised by mainstream politicians and a disturbingly large segment of the mainstream media.”

The Metropolitan police said: “[A man in his thirties] was attacked by up to four males, who also assaulted his friends when they attempted to intervene. None of those injured required hospital treatment or London ambulance service. No arrests have been made.”

Katharine Viner, editor-in-chief of the Guardian and Observer, said: “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.”

Labour leader Jeremy Corbyn sent a message of “solidarity” to Jones. He 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.”

Labour MP Diane Abbott also condemned the attack on Twitter: “Shocking to hear about this attack on you & your friends. The times we live in are increasingly dark and dangerous. You have all my love & support. Solidarity.”

Jones thanked his friends “who were assaulted defending me and who I love very much.”