Pre-emptive arrests, confinement by kettling and the gathering of personal data give police officers "excessive and disproportionate" control over public protests, a report by a coalition of police monitoring groups has warned.
The study by the Network for Police Monitoring (Netpol) is highly critical of tactics used by forces across the country to clamp down on what it says are freedoms of assembly and expression.
Based on evidence from court cases and eyewitness reports of police operations in 2010 and 2011, the study calls for a more tolerant approach towards processions and protests.
Netpol consists of an alliance of well-established activist groups, including Aldermaston Women's Peace Camp, the Campaign Against Criminalising Communities, Climate Camp Legal Team, FITwatch, Green & Black Cross, Legal Defence and Monitoring Group and the Newham Monitoring Project.
"The use of pre-emptive arrests is one of the most disturbing aspects of the policing of protest during [this] period," the report states. "The mere possibility of disruption to the royal wedding triggered the arrest of groups of prospective protesters who had committed no criminal acts.
"Ten people holding placards were arrested while heading to a republican party, and a group of people dressed up to attend a 'zombie wedding' were apprehended while drinking coffee in Starbucks."
Intrusive levels of stop and search were used during an anti-austerity demonstration of 30 June 2011, where people were also "pre-emptively arrested for wearing black and looking like an anarchist," the study says.
The high court, however, recently ruled that the use of pre-emptive arrests in advance of the royal wedding in 2011 was lawful. The European court of human rights in Strasbourg has also dismissed appeals by campaigners who have attempted to have kettling – refusing to allow protesters to disperse – outlawed.
The Netpol report disagrees with the court decisions, maintaining that holding people "for long periods of time within police kettles has placed vulnerable individuals at risk, prevented people from moving away from scenes of violence and disorder … and constitutes an unnecessary and unjustified interference with individual liberty".
It adds: "People attempting a spontaneous march from a UKUncut demonstration were held for up to two hours on Lambeth Bridge, in a situation which in no way presented a risk of harm.
"Student protesters in Manchester were similarly kettled for taking part in a demonstration which, while disobedient, was not violent.
"The imposition of a kettle in Whitehall on the 24 December student demonstration appeared to be a catalyst of disorder, and serious injuries occurred in Parliament Square on the 10 December despite the use of kettling."
On the gathering of personal data about protesters by police, Netpol says: "It has been well documented that Forward Intelligence Teams (FIT) compile detailed and personal data on their subjects, including appearance, clothing and associates.
"Becoming a target of a Forward Intelligence Team does not require any involvement in criminal activity, merely a prominent or frequent involvement in political protest." Names and addresses are often demanded.
"We believe that this power is frequently misused to obtain intelligence about individuals who have done nothing unlawful. Protest should not be equated with anti-social behaviour, and the use of such powers on political demonstrations should end."
Used together, the Netpol report concludes, the powers and strategies adopted by the police have allowed them "to exercise an excessive and disproportionate level of control over protest assemblies and processions".