The families of 96 people killed in the Hillsborough tragedy have begun viewing for the first time thousands of official documents relating to the disaster.
The Hillsborough Independent Panel is overseeing the release of previously unpublished papers from around 80 organisations including the government, police, emergency services, Sheffield City Council and the South Yorkshire coroner.
A report explaining the contents of the documents will be published by the panel, chaired by the Bishop of Liverpool, the Rt Rev James Jones.
The families of the 96 football fans who died in Britain's deadliest sporting disaster are the first to see more than 400,000 pages.
The Liverpool supporters died in a crush at Sheffield Wednesday's Hillsborough stadium on April 15, 1989, where their team were meeting Nottingham Forest in an FA Cup semi-final.
The club today offered an apology to the families and said it hoped the documents would bring them "closure".
A statement from Sheffield Wednesday said: "Chairman Milan Mandaric and the current board of directors have adopted a policy of complete compliance with the requests of the Hillsborough Independent Panel and on behalf of the club would like to offer our sincere condolences and an apology to all the families who have suffered as a consequence of the tragic events of 15 April, 1989."
Mandaric took over in December 2010 and the statement added the club had been "totally transparent" in helping the report be compiled.
It added: "Sheffield Wednesday FC welcomes the release of the Hillsborough Independent Panel report and would like to acknowledge the enormous amount of hard work by all involved during what was, and continues to be, an extremely emotive process.
"Throughout the compilation stage, the club has worked closely with the panel and the other donating organisations to ensure that, in line with the ethos of maximum disclosure, we have been totally transparent.
"Sheffield Wednesday would also like to record its gratitude for the thoroughly dignified manner with which the Hillsborough Family Support Group and its representatives conducted themselves throughout all levels of consultation with the club.
"We can only hope that the publication of the report goes some way to providing the closure sought by all those involved."
Relatives and survivors began arriving at Liverpool Cathedral from 8am where they met members of the panel and viewed the documents.
Speaking earlier, Margaret Aspinall, chairwoman of the Hillsborough Families Support Group, said they hope the documents will answer some of the questions they have about the causes and aftermath of the tragedy.
"This is what the families and the fans have been fighting for 23 years. Without the truth you cannot grieve and where there is deceit, you get no justice," Mrs Aspinall, 65, said.
Prime Minister David Cameron will address MPs in the House of Commons following PMQs and the documents will be uploaded to a website for viewing by the general public.
A report into the disaster by Lord Justice Taylor, published in 1990, found that the main reason for the disaster was a failure of "police control" but the Crown Prosecution Service decided there was insufficient evidence to bring a prosecution.
The victims' families say it is an injustice that no individual or organisation has been held fully accountable for the disaster. They believe a major incident plan was never initiated by South Yorkshire Police and fans in the Leppings Lane end were denied emergency medical attention.
The families also dispute the findings of an inquest into the deaths, which ruled that the victims were all dead, or brain dead, by 3.15pm and which subsequently recorded a verdict of accidental death.
It is expected the families will meet in the coming days to decide what action to take, if any, following the disclosures.
They are being advised by two of Britain's best known lawyers, Michael Mansfield and Lord Falconer.
The panel was created by then home secretary Jacqui Smith following the 20th anniversary of the disaster in April 2009.
Central to the panel's work is to prepare and publish a comprehensive report based on in-depth research into the documents to "add to public understanding of the tragedy, its circumstances and its aftermath".
Downing Street confirmed that Mr Cameron received a copy of the Hillsborough report this morning, after it was seen by the families.