Clashes at G20 protest Climate Camp - Video courtesy of The Sunday Times
Campaigners have called for a "truly independent" inquiry into allegations that police used unnecessary violence to evict the G20 climate camp.
The Camp for Climate Action has dismissed an already-announced inquiry into the policing of G20 protests as "the police investigating themselves".
A new report contains fresh allegations of police brutality at the camp, set up in the city of London on April 1.
But the police have defended their actions on the day as "proportionate".
The Climate Camp's report has been sent to MPs, ministers and the Independent Police Complaints Commission (IPCC) in the hope of garnering support, say campaigners, for an inquiry free of police or ministerial interference.
The protesters say they have doubts about the independence of the current inquiry, commissioned by the Metropolitan Police, and chaired by senior ex-Met officer Denis O'Connor for Her Majesty's Chief Inspector of Constabulary (HMIC).
Mr O'Connor will be looking into three cases of alleged G20 police brutality - including the death of newspaper seller Ian Tomlinson, as well as the tactics officers employed on the day.
On Monday it was revealed that a third post-mortem could be ordered into Mr Tomlinson's death.
It is thought the post mortem request may have come from the representatives of the police officer at the centre of the allegations.
So far the Independent Police Complaints Commission has had almost 90 complaints relating to the London protests.
A Climate Camp spokeswoman wrote: "We are concerned about the independence of [the HMIC] from the Home Office and the police and that it essentially involves, as we understand it, a senior ex-Met officer investigating the Met which we do not think is satisfactory.
"We are concerned that it is essentially the police investigating themselves.
"We call for parliamentarians to back calls for an inquiry into the policing of protest... undertaken by someone or somebody truly independent of the police and the Home Office."
The Home Office rejected the charge.
A spokesman said: "HMIC is the independent Inspectorate of policing in England, Wales and Northern Ireland and was established under statute.
"The home secretary is absolutely clear on the importance on that independence."
The campaigners' report, Demonstrating Respect for Rights, contains new allegations about how police used violence to clear the area in front of the European Climate Exchange during the evening of April 1.
The protesters say once journalists had left the area, officers used shields and truncheons against "non-violent" campaigners who had hoped to set up a 24-hour climate camp protest.
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