For 22 years Margaret Thatcher's cabinet papers on her involvement with the inquiry into the causes of the Hillsborough football disaster have remained sealed.
Ninety-six fans were crushed to death at the 1989 FA cup semi-final between Liverpool and Nottingham Forest being staged at the Hillsborough stadium in Sheffield.
She visited the ground on the morning after what has gone down in history as one of football's worst ever disasters.
Notes on cabinet discussions held at the time could reveal exactly what the prime minister was being told about the causes of the tragedy.
Those cabinet papers have been sealed under the 30-year disclosure rules and successive governments have refused to make an exception.
They were not seen by the inquiry chaired by Lord Justice Taylor which reported in 1990 and recommended that all football grounds should be converted to all-seater stadiums.
An online e-petition is now set to change all that.
The government set up a web page allowing members of the public to launch e-petitions on any subject.
It came with a promise that if any attracted more than 100,000 supporters a full-scale parliamentary debate would be held.
Few would have anticipated that it would unleash the political power of football fans.
In August a petition was launched demanding the release of all government papers on the Hillsborough tragedy.
Within 24 hours of it being posted 13,500 had signed up.
As the victims were largely Liverpool fans the club's current manager Kenny Dalglish sent out a message on Twitter urging supporters to sign. Other Liverpool footballing legends did the same.
Within a week the petition had attracted 50,000 signatures.
A week later it passed the 100,000 mark. Almost 40,000 more have since signed up.
Their online muscle means that the Hillsborough disaster has become one of the first of two petitions to trigger a House of Commons debate.
"I was one of the lucky ones. I made it back," says Steve Rotheram, now the Labour MP for Liverpool Walton but at the time a fan at the game.
"For all we know this may not shed any further light on what went wrong at Hillsborough but it will reassure families who have always wondered what Margaret Thatcher knew."
Clive Betts, Labour MP for Sheffield South East, was also at the match. He was leader of the city council at the time and was a VIP guest at the semi-final.
"I intend releasing all my papers on Hillsborough from my time as council leader," he said.
"We owe it to the fans to show them that every aspect of this tragedy is available for them to see."
The government appears to have taken account of the e-petition.
It has already said it will release all the papers to a panel which was appointed by the previous Labour government to look into the tragedy. It hopes to report next spring.
The debate in the House of Commons takes place on Monday 17 October.