A man was stabbed as dozens of 'Polish neo-Nazis' stormed a free music event sparking violent clashes in a north London park, witnesses said.

Flares, rocks and glass bottles were thrown during an "unprovoked attack" in Tottenham on Saturday night.

A 24-year-old man Polish man was knifed during the violence after a neo-Nazi group disrupted a free Music Day festival of around 150 people in Markfield Park. Anti-fascist campaigners said up to 40 neo-Nazis had planned an event of their own nearby but stormed the family music event.

Video footage of the clashes show a single female police officer at the scene as thugs hurl missiles, light fires and hurl abuse.

Witness Oz Katerji, a journalist, tweeted: "About 150 of us were having a party in Markfield Park in Tottenham, Neo-nazi polish fascists turn up, full scale riot operation.

"Unprovoked assault at a licensed event, children present, maybe about 10-20 skins turned up and started a riot," he added.

Haringey Green Party claimed the attack was carried out by members of the Zjednoczeni Emigranci (ZE) fascist group, which is alleged to have ties to football hooliganism and neo-Nazism in Poland.

A statement from the Greens said: "Taking the peaceful community event by surprise, ZE launched an unprovoked attack, hurling verbal abuse at locals, intimidating the children and families that were present, before turning to physical violence. Footage from the community event shows ZE launching rocks and flares at the crowd."

Police confirmed a man was taken to hospital with stab wounds but said his condition is not believed to be serious. Nobody has been arrested in connection with the stabbing.

A Polish man from Surrey has been charged with racially and religiously aggravated common assault and has been bailed to appear in court in July. Another man, aged 22, was arrested for racially aggravated common assault after a man's kippah was pushed from his head, according to police.

A spokesman said: "Police were called at approximately 21:10hrs on Saturday, 21 June to a disturbance at Markfield Recreation Ground, N15.

"Officers attended the location. A 24-year-old man was found suffering from a stab wound. He was taken by London Ambulance Service to an east London hospital where his condition is not believed to be serious. Officers from Haringey CID are investigating."

The Music Day event was one of hundreds of linked concerts held around the world on Saturday to "celebrate the universal language of music". At least a dozen linked events were held in London alone at the weekend.

Campaign group Unite Against Fascism is today holding a demonstration after the clashes.

A statement on the group's Facebook page said: "After a neo-Nazi attack in Markfield Park, Tottenham, North London, yesterday, join a peaceful vigil tomorrow (Monday 23 June), 6 PM at Tottenham Green (opp Tottenham Town Hall); called by UAF. Fascists are not welcome in Tottenham!"