An illegal London street party turned into a violent anti-police riot when officers tried to shut it down — with disturbing footage appearing to show one man waving a sword at a line of cops.

Scotland Yard says at least 22 officers were injured Wednesday night as the large crowd turned against them after they tried to shut down a “large unlicensed music event” in Brixton.

Videos show several people jumping on a squad car, using makeshift weapons to smash all its windows — while another clip shows a man waving a sword and telling cops to “back up,” the Evening Standard said.

Even officers with riot gear were forced to back off as missiles were hurled, the Standard said.

“Welcome to Brixton,” some social media clips were captioned, referring to the south London area’s troubled history that has included some of the nation’s worst riots.

Despite the ugly scenes and number of injured officers, only four people were arrested for assault and public order offenses, Scotland Yard said.

Home Secretary Priti Patel condemned the “utterly vile scenes.”

The Metropolitan Police Federation’s chairman, Ken Marsh, described it as an “absolute volley of anger and hatred towards the police,” saying, “Police officers are not punchbags.”

“This violence is despicable. Yet again our brave colleagues in London have come under attack,” he said.

“My colleagues are human beings as well — and suddenly in scenes like last night they’re confronted by people who ultimately want to cause them grievous damage.”

He insisted, “My colleagues are faced with all sorts of trauma from these incidents.”