The number of police officers to be investigated over their role in the Hillsborough disaster and its cover up is set to reach at least 2,444 from 20 different forces.
The Independent Police Complaints Commission said that up to 1,000 more officers were likely to feature in the inquiry than it had originally announced.
Chief executive of the IPCC Jane Furniss, told MPs at a meeting of the Home Affairs Select Committee that forces across the country had contacted the authority to volunteer names of staff either present at the match or involved later.
Investigators will then seek to establish which of those will be questioned as part of the inquiry into police conduct in the wake of the tragedy.
The final number is expected to be considerably smaller although the majority will be from South Yorkshire, which was responsible for the policing of the 1989 semi-final between Liverpool and Nottingham Forrest in which 96 fans died, as well as from the West Midlands which was charged with leading the ensuing investigation into South Yorkshire Police.
A further 18 forces are also expected to be drawn into the investigation which MPs were earlier told by the Director of Public Prosecutions Keir Starmer, could lead to prosecutions for perverting the course of justice.
Three of those forces are said to be involved in a significant way.
Ms Furniss also revealed that not all the documents relating to the disaster were passed to the Hillsborough Independent Panel whose devastating report has seen a new investigation launched into possible wrongdoing following the tragedy and new inquests into the deaths likely to be announced.
She said: “Because of the level of contact we are now having with families, bereaved families, and survivors we are already hearing quite significant members of the public who were at the match who said I tried to make a statement and wasn't allowed to, or I made a statement and that (which) is on the website isn't the statement I made, or I was bullied into withdrawing information.”
Ms Furniss said the Home Secretary had assured the IPCC that it would have sufficient resources to investigate the tragedy. Mr Starmer said no timetable had been set for the investigation.