Here is a look back at some of the milestones in the 32 years following the Hillsborough disaster.

– April 15 1989: Ninety-six football fans are fatally injured in a deadly crush as Liverpool play Nottingham Forest in the FA Cup semi-final at Sheffield Wednesday’s Hillsborough ground.

– April 1989: Lord Justice Taylor is appointed to conduct a public inquiry into the disaster, with the West Midlands Police force later instructed to examine the role of its South Yorkshire counterparts.

– August 4 1989: An interim Taylor Report is published into the disaster after the submission of 3,776 written statements of evidence, 1,550 letters, 71 hours of video footage and the oral evidence of 174 witnesses.

– January 1990: The full Taylor Report finds the main reason for the disaster is the failure of police control and the decision to open Gate C without blocking the tunnel to central pens, calling them “blunders of the first magnitude”.

– April 18 1990: South Yorkshire coroner Dr Stefan Popper begins the first inquests in Sheffield. A 3.15pm cut-off point is imposed so inquiries into lack of emergency response are ruled inadmissible.

– March 28 1991: After the longest inquest in British history to date, lasting 90 days, a verdict of accidental death is returned by a majority verdict of 9-2.

– November 1991: Chief Superintendent David Duckenfield, who was in charge of the police operation on the day of the disaster, resigns on a police pension due to ill health.

– March 1993: Families seek a judicial review of the inquest, which is initially dismissed, then appealed against, then rejected by the Royal Courts of Justice, which rules the original inquests should stand.

– May 1997: New Labour government home secretary Jack Straw appoints Lord Justice Stuart-Smith to conduct a “scrutiny of evidence”, but he concludes new inquests are not warranted.

– July 2000: Mr Duckenfield and the ground commander on the day Superintendent Bernard Murray stand trial in Leeds charged with manslaughter in a private prosecution brought by the families. Mr Murray is cleared but the jury fails to reach a verdict on Mr Duckenfield.

– November 2006: Anne Williams, whose son Kevin, 15, died in the disaster, submits her case to the European Court of Human Rights (ECHR).

– March 2009: The ECHR rules Mrs Williams’s case should have been lodged earlier and is “out of time”.

– April 15 2009: Minister Andy Burnham is barracked while speaking at the 20th anniversary memorial at Anfield. He raises the matter at Cabinet and three months later the Home Office announces full disclosure of all information to be looked at by an independent panel.

– September 12 2012: A Hillsborough Independent Panel (HIP) report is critical of blame put on to fans. Prime minister David Cameron offers in the Commons a “profound apology” for the “double injustice”.

– October 12 2012: The Independent Police Complaints Commission launches its biggest ever investigation into police in the UK, centred on officers’ conduct over Hillsborough.

– December 19 2012: The High Court quashes the accidental death verdicts in the original inquests and orders new ones. The same day, home secretary Theresa May announces a new criminal probe to investigate “all of the people and organisations involved – before, on, and after” the disaster.

– March 31 2014: New inquests begin at Birchwood Park, Warrington.

– April 26 2016: The inquest jury delivers its verdict, and finds that the 96 Liverpool fans were unlawfully killed. It finds that blunders by South Yorkshire’s police and ambulance services “caused or contributed to” their deaths, and exonerated Liverpool fans of wrongdoing. South Yorkshire Police Chief Constable David Crompton admitted the force got the policing of the match “catastrophically wrong” and “unequivocally” accepted the inquest jury’s conclusions.

– June 28 2017: The Crown Prosecution Service announces six men will be charged following investigations into the disaster. Retired South Yorkshire Police chief superintendent Donald Denton, former detective chief inspector Alan Foster and solicitor Peter Metcalf are charged with doing acts with intent to pervert the course of public justice in relation to the process of amending statements. Former Merseyside and West Yorkshire chief constable Sir Norman Bettison is charged with four offences of misconduct in public office. Former Sheffield Wednesday secretary Graham Mackrell is charged with two offences of contravening a term of condition of a safety certificate contrary to the Safety of Sports Grounds Act 1975 and a health and safety offence. The CPS says Mr Duckenfield will be charged with manslaughter by gross negligence once a stay imposed after his earlier trial is lifted.

– June 29 2018: Judge Sir Peter Openshaw lifts the stay, meaning Mr Duckenfield will face trial. The prosecution decides not to proceed with one of the three offences Mr Mackrell is charged with.

– August 28 2018: Proceedings against Sir Norman Bettison are dropped by the prosecution, who say “the state of the evidence has changed” following the death of a witness.

– January 14 2019: The trial of Mr Duckenfield and Mr Mackrell begins at Preston Crown Court. One of the two remaining offences Mr Mackrell is charged with is dropped.

– April 3 2019: After 29 hours and six minutes of deliberations, the jury finds Mr Mackrell guilty of failing to discharge his duty under the Health and Safety at Work Act. Jurors are unable to reach a verdict on Mr Duckenfield.

– May 13 2019: Mr Mackrell is fined £6,500 and ordered to pay £5,000 costs for failing to ensure the health and safety of fans arriving at the ground on the day of the disaster.

– October 10 2019: The retrial of Mr Duckenfield is opened.

– November 29 2019: After a six-week case, Mr Duckenfield is cleared of manslaughter by gross negligence. Families call the trial a “disgrace”.

– April 20 2021: The trial of Mr Denton, Mr Foster and Mr Metcalf is opened at the Nightingale court sitting at the Lowry Theatre in Salford.

– May 26 2021: The three defendants are formally found not guilty after judge Mr Justice William Davis rules there is no case to answer.