Government workers are believed to have posted insulting remarks, ridiculing the victims of the Hillsborough disaster online.
According to the Liverpool Echo, a number of computers behind Whitehall's secure Intranet were used to deface several Wikipedia pages.
The Hillsborough Wikipedia page in particular was heavily targeted. Inflammatory phrases, including "blame Liverpool fans," "You'll never w*nk alone" and "You'll never walk again" were added to the encyclopedia entry.
The accusations have prompted the Cabinet Office to launch "urgent inquiries" into the matter.
"We thank the Liverpool Echo for bringing this to our attention," said the Cabinet Office. "This is a matter that we will treat with the utmost seriousness and are making urgent inquiries."
The Echo says that IP addresses within government departments, including the Treasury and the Office of the Solicitor General, were used to make the changes. The newspaper also claims that the Wikipedia changes were made five years ago on the 20th anniversary of the disaster, and then again two years ago.
"No one should be in any doubt of the government's position regarding the Hillsborough disaster and its support for the families of the 96 victims and all those affected by the tragedy."
On 15 April 1989, 96 people football fans were crushed to death and hundreds more were injured as a result of overcrowding during the FA Cup semi-final between Liverpool and Nottingham Forest, at the Hillsborough Stadium in Sheffield.
It remains one of the biggest tragedies in sporting history, and the truth around the case has still not been solved. Many blame the police for gross incompetence and corruption. An enormous contingent of football supporters - most famously those affiliated with Liverpool FC - have campaigned for justice ever since the disaster took place.
2014 marks the 25th anniversary of the incident.
"I don't know how to react, it's just so sad," said the Hillsborough Family Support Group's Margaret Aspinall. "I hear something like that and it upsets me a great deal, it makes me incredibly sad. I'm glad someone has found out about it but I'm frightened, to be honest, that we haven't known until now."
Also heavily vandalised was the Anfield page, with the description of much-revered former Liverpool manager Bill Shankly edited and a reference to the iconic "This is Anfield" banner transformed to read as "This is a sh*thole".
Image credit: HDRSpotting