The Government has been ordered to release documents recording the talks held by Margaret Thatcher about the 1989 Hillsborough disaster which claimed 96 lives.
The Information Commissioner, Christopher Graham, ruled that the release was in the public interest and said the papers would "add to public knowledge and understanding" of reactions to the tragedy.
A freedom of information request by the BBC two years ago was blocked by the Cabinet Office and the Information Commissioner was asked to review the refusal. The Cabinet Office has 35 days to comply, unless there is an appeal.
The Government had argued that to release the records would impinge on the willingness of ministers to speak openly.
In the tragedy at Hillsborough, Sheffield Wednesday's football ground, scores of Liverpool fans were crushed to death because of overcrowding that an inquiry blamed primarily on the failure of police to control the crowds.