Yesterday saw another round of student protests across the UK, with students marching and occupying buildings from one end of the country to the other. In London, protestors led police on a merry chase across the city, breaking from their march route to avoid a police attempt to kettle them, but at the end of the evening a group ended up kettled in Trafalgar Square. At the end of the evening, the police arrested everyone present, ostensibly in reaction to a few people graffiting Nelson's Column (making it an indiscriminate response), but in reality to shut down the protest and force people to go home. Again, we see the ugly attitude from the UK police: protests are inherently a threat to public order, and must be suppressed. This attitude is simply not consistent with democratic government, or with the UK's obligations under its own Human Rights Act, the European Convention on Human Rights, or the ICCPR.
If people want to protest in a public space in the cold at nine o'clock at night, that is their absolute right. Freedom of expression and the freedom to protest are not confined to ordinary business hours, but operate 24/7. And if the police get bored of over-reacting after a long day of standing around in body-armour with batons drawn, that's their own problem.
Unfortunately, there's no effective comeback for this sort of abuse of power. Charges can be dismissed by the courts (or simply dropped by the police) - but the damage has already been done. Meanwhile, those who made the decision to conduct mass arrests to undermine the public's right to protest will keep their jobs, and will never face any charges themselves. In the UK, violating the public's rights is not a crime. And until that changes, the police will continue with this sort of abuse.