By Sachin Ravikumar and Kylie MacLellan
LONDON (Reuters) -British police remained on alert on Thursday after a heavy security presence, rapid arrests and displays of unity by people across Britain on Wednesday prevented a repeat of widespread rioting involving racist attacks targeting Muslims and migrants.
After police deployed in force and thousands of anti-racism protesters took to the streets on Wednesday evening, threats of widespread gatherings by far-right anti-immigration groups did not materialise.
But the government said it was still cautious after days of riots triggered by false online posts wrongly identifying the suspected killer of three young girls in a July 29 knife attack in Southport, northwest England, as an Islamist migrant.
Police said a further potential 20 gatherings and three counter-gatherings were planned for Thursday.
"We're going to continue the strong policing response, making sure that there are additional police officers ready to respond," interior minister Yvette Cooper told reporters.
More than 480 people have been arrested across the country so far, with nearly 150 charged. Dozens have already been sentenced with cases fast-tracked through the justice system.
Britain's most senior police officer, London Commissioner Mark Rowley, said many of those arrested had criminal backgrounds.
For Prime Minister Keir Starmer, a former chief prosecutor, it is the first major test of his premiership since winning a July 4 election in which the previous Conservative government highlighted immigration as a major issue.
Rowley dismissed suggestions the riots were political.
"Any suggestion they're patriots, or they've got a cause... is nonsense," Rowley said. "They're criminals."
Several thousand people from anti-racism groups gathered in Walthamstow, north London, on Wednesday following threats to an immigration advice centre there. Others protected mosques and hotels housing asylum seekers that were among other targets.
Rowley hailed a "successful" night that had gone "very peacefully" apart from a few criminal incidents.
Footage circulated on X showed a councillor from Starmer's Labour Party at the Walthamstow gathering calling for people to cut the throats of "disgusting Nazi fascists."
London police said a man in his 50s had been arrested on suspicion of offences including encouraging murder. Labour said the behaviour was "completely unacceptable" and the man, a councillor in Dartford, Kent, had been suspended from the party.
'BETTER THAN EXPECTED'
Sentencing of those involved in disorder over the past week continued on Thursday, with prison terms of between 11 and 32 months handed out. On Wednesday, one man was jailed for three years. Convictions have also included those who encouraged violence online.
Fast and tough judicial action was viewed as helping quell the last serious nationwide rioting in England in 2011, for which almost 4,000 people were arrested.
Starmer, who met with police and community leaders in Birmingham on Thursday, said Wednesday night was "much better than expected". He is holding an emergency meeting with police on Thursday to discuss efforts to contain any further riots.
More than 100 police officers have been injured since the start of the rioting, including broken limbs.
"I was very keen that we're able to demonstrate that if you're involved in disorder, within days, you'll be in the criminal justice system," he told reporters. "That needs to continue."
No large far-right gatherings were reported on Wednesday.
According to Logically, a company which works with governments and other organizations to reduce the harm of misinformation, the planned disorder had been coordinated by an international network of extreme right-wing Telegram channels with links to banned groups.
Former members of banned neo-Nazi groups Atomwaffen Division and National Action had joined U.S.-founded Active Club networks of white supremacist groups, neo-Nazis, and those of nationalist soccer hooligans to stoke tension and provoke clashes. They were among the first to share a list of targets, Logically said.