Nigel Farage is giving legitimacy to violent protesters and excusing disorder that police chiefs fear will continue into the weekend, a metro mayor has said. At least 19 far-right rallies are being planned across England in the coming days, the Guardian understands. One of the UK’s most senior police officers has said preparations are in place for what could be considerable disorder over the weekend. There have been violent demonstrations in Southport, London, Hartlepool and Aldershot since the stabbings in Southport on Monday in which three young girls died. Police officers have been hospitalised after being attacked by bricks and other missiles, property has been destroyed, cars set alight and local people have been terrified. Farage, the recently elected MP for Clacton, released a video on Thursday evening in which he said he did not support street violence but added: “What you’ve seen on the streets of Hartlepool, of London, of Southport is nothing to what could happen over the course of the next few weeks.” Steve Rotheram, the metro mayor of Liverpool city region, told ITV’s Good Morning Britain: “Whilst senior politicians like Farage should be condemning these people – he’s not, he’s excusing them. He’s giving them some legitimacy to go out and perpetrate some of these acts.” Gavin Stephens, the chair of the chief National Police Chiefs’ Council, said forces were preparing for what could be considerable disorder over the weekend. “It’s our job in policing to do that,” he told BBC Radio 4’s Today programme. It’s our job to be worried on behalf of communities, to be prepared, to be there.” Stephens said people with responsibility, whether community leaders, social media platform providers or police, all had a responsibility “to make sure that this violence is not inevitable”. He said police chiefs had agreed to step up resources over the weekend. “We will have surge capacity in our intelligence, in our briefing and in the resources which are out in local communities.” There would also be additional prosecutors available “to make swift decisions so we see swift justice”. Neil Basu, a former head of counter-terrorism policing, said on the Today programme that Farage “should think very carefully” about the power of his words. Predicting a “long, hot summer” for police forces, he said: “That is a far-right politician once again trying to direct policing and law and order. He doesn’t speak for tens of millions of people, the prime minister does – who has to serve the whole population, not just the ones he likes. “And this is not the first time a politician has tried to interfere with operational policing, particularly from that section of politics.” Lord Walney, the UK government’s adviser on political violence and disruption, said police should be prepared to step in if it appeared troublemakers were travelling to incite riots. He told BBC Scotland there was a “concerted and coordinated” attempt to spread the violence. “Clearly, some of those far-right actors have got a taste for this and are trying to provoke similar in towns and cities across the UK. “The police do have powers to be able to identify the troublemakers, there are new laws in place which can restrict the movement of those who are known and have a track record of violent or illegal disruption and criminality. “They should be stopped from coming to the sites of protests as they’re being organised.” The leader of Glasgow council has told Tommy Robinson directly that he is not welcome in the city after the English Defence League founder announced a “pro-UK” rally in the city’s George Square next month. Susan Aitken said: “Glasgow city council has received no notification of any rally but then we know Tommy Robinson and his ilk don’t really care about respecting laws or public places. He’s not welcome in Glasgow and neither is anyone who chooses to align with his poisonous rhetoric.” The Scottish Labour leader, Anas Sarwar, one of Scotland’s most prominent Muslims, said he had no doubt that Glasgow would reject the rally. “There have been attempts by the far right before to do protests here or to sow divisions here,” he said. “Every single time the far right has tried to do that in Glasgow, Glasgow has overwhelmingly rejected them.” Merseyside police said they had arrested seven people on Friday, with further arrests to be made over the coming days in connection with the disturbances in Southport. Seven men, aged between 28 and 54, are due on Friday to appear before Teesside magistrates in Middlesbrough following Wednesday night’s disorder in Hartlepool. An 11-year-old boy has also been arrested on suspicion of arson after a police vehicle was set alight during disorder described by witnesses as mindless. Imam Ibrahim Hussein, the chair of Southport mosque, told the BBC on Friday that violence in his town earlier this week had been “terrifying” and were “horrific scenes”. But he also said the supportive, loving response from the local community had been invaluable. “We are grateful for their support and we are grateful to be in such a neighbourhood. We are a normal part of the community. We love them and they love us.”