The Independent Police Complaints Commission is calling for witnesses who were at Hillsborough and gave their accounts to police to come forward as part of its investigation into the aftermath of the disaster.

The investigation, which is the biggest undertaken into police conduct in England and Wales, is examining police actions following the stadium disaster. This includes how West Midlands Police, the force appointed to accumulate evidence for Lord Justice Taylor's inquiry and the subsequent inquests, conducted its inquiries.

It is known that thousands of members of the public gave witness accounts to West Midlands Police, either in writing, via telephone or in face-to-face interviews. The IPCC wishes to speak with these people to understand more about their experiences and the process they went through.

If you gave an account to West Midlands Police, the IPCC would like to hear from you. A dedicated Hillsborough Witness Appeal online witness appeal form can be found at www.ipcc.gov.uk/hillsborough-witness-appeal.

If you do not have access to the internet, or need assistance in completing the form, call 0300 200 0003.

Deborah Glass, deputy chair of the IPCC, said: "Our investigations are making real progress. We have made significant discoveries already in relation to additional amended statements, West Midlands Police policy files and pocket notebooks from South Yorkshire Police officers. Now we are looking for the assistance of the public as we examine how West Midlands Police conducted its investigation into the disaster.

"We want to hear from anyone who contributed to that investigation. If you gave an account, what was your experience? Do you believe that you were given the opportunity to reflect your experience at Hillsborough? I appreciate that for many it will be incredibly difficult to revisit the events they experienced and witnessed on April 15, 1989. But I would urge you to contact us to help our investigation. There will be appropriate welfare and support offered to those who require it.

"It is the IPCC's objective to deliver a full, thorough and robust investigation into the aftermath of the Hillsborough disaster. I want to ensure that this is the definitive and final investigation into the Hillsborough disaster. This can only happen with your help."

To read more about the IPCC's Hillsborough investigation click here.

The Hillsborough Investigation

On October 12, 2012, the IPCC launched an independent investigation into allegations of police misconduct or criminal behaviour during the aftermath of the Hillsborough disaster, following the publication of the Hillsborough Independent Panel's report.

This investigation is looking specifically at amendments to statements, the actions and conduct of South Yorkshire Police officers after the disaster, the role of West Midlands Police and those who investigated what happened at the time.

Operation Resolve is a strand of the Hillsborough investigation being led by former Durham Chief Constable Jon Stoddart. This part of the investigation is looking at the events leading up to the match at Hillsborough, as well as the disaster itself. A range of organisations will be investigated as part of Operation Resolve, such as Sheffield Wednesday Football Club, The Football Association, South Yorkshire Ambulance Service. South Yorkshire Police will also be investigated by Operation Resolve, and the IPCC is managing this part of their work, providing oversight.

Both investigations will run separately, but work closely alongside one another, as well as with agencies such as the Crown Prosecution Service and the Coroner, in preparation for the new inquests set for March 2014.