London police on Tuesday arrested Swedish activist Greta Thunberg at a demonstration in support of pro-Palestinian hunger strikers, Palestinian activist groups said. Thunberg’s arrest makes her the highest-profile person to be detained by police since the government banned the Palestine Action group under anti-terror laws. “Greta Thunberg was arrested under the Terrorism Act at the Prisoners for Palestine lock-on protest,” Prisoners for Palestine said in a statement.