A national plan to mobilize British police was triggered three days too late during anti-immigration riots that shook the country this summer, an official report said Wednesday, in part because intelligence assessments didn’t accurately predict the scale of the violence.

The report, which was published by the institution that oversees policing in England, underscores the challenge facing law enforcement in an era when online misinformation spreads rapidly and can result in real-world disorder.

Unrest gripped Britain for the better part of a week in late July and early August, after a 17-year-old killed three girls and wounded others at a dance class in Southport, near Liverpool. After false information about the attacker spread online, anti-immigrant and far-right mobs set fires, attacked the police and mosques, looted stores and targeted hotels housing asylum seekers.

The report, commissioned by the U.K. government after the riots, examined the response of eight police forces in areas where the unrest unfolded.

While it praised the work of officers for displaying “immense bravery in the face of extreme violence,” the report criticized the National Police Chiefs’ Council, which coordinates the response of police across the country, for not launching a national plan to tackle the riots earlier.

The mobilization effort, which involved greater deployments around the country and using more specially trained officers, was not triggered until Monday, Aug. 5. The report concluded that the council should have acted on Aug. 2, when it became clear that the disorder was escalating.