Police faced new accusations of brutality against G20 protesters today.

Lawyers acting for climate change protesters will deliver a dossier to the Independent Police Complaints Commission (IPCC) containing hundreds of witness statements.

Activists claim that they were attacked by police who broke up their Climate Camp in the City of London on the evening of April 1.

Officers are accused of using shields and truncheons against "non-violent" campaigners outside the European Climate Exchange.

Louise Broadbent, 27, said she was attacked twice "for no reason at all" by officers "using their riot shields as weapons".

The asthma sufferer said she was prevented from leaving an area being "kettled" - a police tactic of enclosing protesters and not allowing them to move on.

A police medic told her "they were under orders not to let anyone out under any circumstances, even for medical reasons", she said.

The dossier also calls for police to wear large numbers on the front and back of their uniforms so they can easily be identified.

Lawyers accuse officers of trying to hide their identities and targeting protesters carrying video cameras.

The IPCC is already carrying out three investigations connected to the G20 protests.

The death of Ian Tomlinson from internal bleeding has resulted in the suspension of an officer seen clubbing the newspaper seller and shoving him to the floor.

Investigators are also examining an allegation of assault by a sergeant seen slapping Nicola Fisher in the face before beating her across the legs with his truncheon.

The incident took place at a vigil for Mr Tomlinson the day after he died.

The third investigation concerns a 23-year-old man who claims he was dragged to the floor and hit several times by a police officer.

The head of the IPCC, Nick Hardwick, will appear before the Home Affairs Committee tomorrow alongside Chief Inspector of Constabulary (HMIC) Denis O'Connor.

Keith Vaz, the Labour chairman of the committee, said MPs would examine the controversial "kettling" tactic used to contain demonstrators.

Mr Vaz said MPs "will obviously want to look at what happened at the G20 protests" and the scope of the IPCC investigation.

He said: "I have faith in the IPCC. I think it's important that we have an independent body that looks into complaints against the police and we don't rush to judgment."

At the weekend Mr Hardwick said he had "serious concerns" about front-line supervision of officers at this month's demonstrations.

He also said police needed to remember that they were "servants, not masters" of the people.

He said he was concerned about officers disguising or removing their identity numbers.

"I think that raises serious concerns about the front-line supervision. Why was that happening, why did the supervisor not stop them?" he said.

"I think that is unacceptable. It is about being servants, not masters: the police are there as public servants."