EPPING: Concern is mounting in Britain that recent violent anti-immigrant protests could herald a new summer of unrest, a year after the UK was rocked by its worst riots in decades.

Eighteen people have now been arrested since protests flared last week outside a hotel housing asylum seekers in the town of Epping, northeast of London, and seven people have been charged, Essex police said. In one demonstration, eight police officers were injured.

The unrest was “not just a troubling one-off,” said the chairwoman of the Police Federation, Tiff Lynch.

“It was a signal flare. A reminder of how little it takes for tensions to erupt and how ill-prepared we remain to deal with it,” she wrote in the Daily Telegraph.

• Anti-migrant sentiments have been amplified by inflammatory messaging on social networks, fueled by far-right activists.