Police in London have raided a warehouse used by Extinction Rebellion, as well as an arts centre that was exhibiting some of the structures used in the demonstrations that blockaded newspaper printing plants last year. The Met is under increased scrutiny as the group plans further protests against the owners of the UK’s press outlets this weekend, alongside supporters of the Black Lives Matter campaign against racial injustice. Scotland Yard said it had “taken proactive action to prevent and reduce criminal disruption which we believe was intended for direction at media business locations over the weekend”. A spokesperson added that 12 people had been arrested in three raids across London. “During the arrests, a number of items were seized by officers, including bamboo structures, lock-on equipment and other items which could be used to cause criminal damage and obstructions. Those arrested have been taken to police custody as inquiries continue.” Extinction Rebellion said the raid at its premises had uncovered only activists making art and questioned why officers had raided the Antepavilion centre, which they said had no connection to them other than exhibiting a bamboo structure used in their blockade of printing presses at last year’s anti-press protest. Police said they were “preparing for what is expected to be a busy weekend”, with marches planned in Westminster, Lambeth and Southwark. The climate crisis demonstrators plan to gather at midday on Sunday in Parliament Square. They said they wanted to highlight that “four tax-avoiding, climate sceptical billionaires – Rupert Murdoch, Lord Rothermere, Sir Frederick Barclay and Baron Evgeny Lebedev – own 68% of the UK’s print media, manipulating the truth and sowing division among the general public for profit”. They have accused the home secretary, Priti Patel, of putting extra pressure on police to crack down on their demonstration in case they target media organisations again. One of the activists, Nuala Gathercole Lam, said: “This is what happens when you take peaceful protest action to the true centres of power in this country. “Four billionaires control the lion’s share of our news and it affords them a vast corrupting influence over democracy. Not only have they become kingmakers in our elections, but they are standing in the way of a national conversation about how we meet the vast challenges the climate and ecological crises present for everyday life.” Ch Insp Joe Stokoe, from the Met police’s public order command, said: “We believe certain protest groups are specifically intending to disrupt some business locations or potentially cause criminal damage to property. If this happens, we will take further action as required to prevent offences being committed or deal with anyone committing criminal acts. “Today, we took proactive action to prevent and reduce the likelihood of criminal activity during the course of the weekend. This action should further demonstrate our commitment and proactivity to preventing criminality.”