The head of the police complaints watchdog is due to face questions from MPs about the policing of the G20 protests.
It comes as a coroner considers a request for a third post-mortem test on the body of a man who died during the demonstrations.
The IPCC's Nick Hardwick will appear before the Commons Home Affairs Select Committee alongside Chief Inspector of Constabulary Denis O'Connor.
Mr Hardwick has said he had "serious concerns" about frontline supervision of officers at this month's demonstrations and told police they needed to remember that they were "servants, not masters" of the people.
Keith Vaz, the Labour chairman of the Home Affairs Select Committee, has said MPs would examine the controversial "kettling" tactic used to contain demonstrators.
On Monday it emerged that the City of London coroner has been asked to order a third post-mortem examination of the body of Ian Tomlinson who died shortly after a confrontation with police during the April 1 protests.
A spokesman for the Independent Police Complaints Commission (IPCC) said: "The IPCC understands that a request has been made for a third post-mortem. This is a matter for the coroner."
The first pathologist to examine the newspaper seller's body concluded that he died of a heart attack but following pressure from his family and the IPCC a second test was carried out and found that the 47-year-old died of internal bleeding.
A police officer captured on video striking Mr Tomlinson with his baton and pushing him to the floor has been suspended and - following the results of the second post-mortem examination - questioned under caution for manslaughter.
Channel Four news reported that the request was made by a police officer although the Metropolitan and the City of London Police both said they were not aware of the force asking for a third test and neither the Police Federation nor the IPCC could shed any light on who had made the request.