A senior MP has claimed that West Yorkshire Police Chief Constable Sir Norman Bettison "boasted" about smearing Liverpool fans in the aftermath of the Hillsborough disaster.
Shadow transport secretary Maria Eagle claimed Sir Norman, who was a chief inspector with South Yorkshire Police at the time of the 1989 tragedy, revealed he had been asked to help "concoct" the force's version of events.
She used parliamentary privilege to make the allegations which were based on new evidence from a witness who discussed the disaster with Sir Norman.
Ms Eagle, a Merseyside MP, said Sir Norman had "always denied any involvement in the dirty tricks campaign".
But she alleged he was behind the "black propaganda" campaign.
She quoted from a letter from John Barry, who was at Hillsborough for the FA Cup semi-final tie that led to the death of 96 Liverpool fans.
The letter, written in 1998 to a solicitor for the Hillsborough Family Support Group, was copied to Ms Eagle in 2009 and she has been given permission to make it public.
Ms Eagle said Mr Barry was studying part-time at Sheffield Business School where one of his fellow students was a "middle-ranking police officer".
Mr Barry wrote:
Ms Eagle said:
Sir Norman, who has announced he will retire in March, faces two investigations by the Independent Police Complaints Commission (IPCC).
The senior officer was referred to the IPCC over claims that he gave misleading information in the wake of the Hillsborough disaster and that he tried to influence West Yorkshire Police Authority's decision-making process in relation to the referral.