Former PM Margaret Thatcher was told a senior Merseyside police officer blamed "drunken Liverpool fans" for causing the Hillsborough disaster, confidential government documents have revealed.

An official inquiry found the main cause of the tragedy was a failure in crowd control by South Yorkshire Police.

Ninety-six football fans died as a result of a crush on overcrowded terraces at an FA Cup Semi Final in April 1989.

The BBC has seen secret papers about Britain's worst sporting tragedy.

Letters to and from 10 Downing Street and cabinet minutes that show what Mrs, now Lady, Thatcher was discussing and being told behind the scenes have been made public for the first time by BBC Radio 4's The World at One.

For years, the families of those who died have been calling for the release of secret government and police papers relating to the disaster.

The government has agreed that this will happen.

The Hillsborough Independent Panel, set up in 2009, is reviewing hundreds of documents but they are not expected to be made available to the families of those who died or to the wider public until later this year.

It is thought there will be thousands of pages to sift through.

The most controversial issue in the papers that the BBC has seen relates to what Mrs Thatcher was being told about the views of some senior members of the Merseyside Police Force.

'Deeply ashamed'

They are contained in a letter sent to the prime minister from a member of her policy unit in Downing Street. Four days after the disaster, the adviser attended a long planned meeting with the chief constable of Merseyside Police, the late Sir Kenneth Oxford, and some of his senior colleagues.

Today's revelations do not constitute a 'smoking gun' but do add to public knowledge about the political reaction to these terrible events Martin Rosenbaum, BBC Freedom of Information expert Martin on the Hillsborough papers

According to the letter, the Merseyside chief constable said: "A key factor in causing the disaster was the fact that large numbers of Liverpool fans had turned up without tickets.

"This was getting lost sight of in attempts to blame the police, the football authorities, etc."

The prime minister was informed that a senior member of the Merseyside Police directly blamed supporters: "One officer, born and bred in Liverpool, said that he was deeply ashamed to say that it was drunken Liverpool fans who had caused this disaster, just as they had caused the deaths at Heysel."

This officer is not named.

More of the views of the chief constable are also referred to:

"He deplored the Press's morbid concentration on pictures of bodies. He was also uneasy about the way in which Anfield was being turned into a shrine".

It is important to bear in mind that this was written just days after the Hillsborough disaster and the views of the chief constable and those of his senior officers may well have changed over the subsequent weeks.

The Merseyside Police force has declined to comment.

'Truth must come out'

There is nothing in the documents the BBC has seen about any briefings from South Yorkshire Police. It is possible more will become known about that when many other confidential papers are officially released in a few months time.

Image caption The government has promised to release files relating to Margaret Thatcher and Hillsborough To abstain from taking action… would be the gravest possible matter, now that the need for this action had been so conclusively demonstrated Margaret Thatcher in 1989 Listen to The World at One programme

Instead, we have learnt about the controversial views of some of Liverpool's own senior police officers and how, just days after the disaster, they were being passed on directly to 10 Downing Street and to Mrs Thatcher.

A spokesman for the panel said it could not comment on the BBC story.

Other Downing Street papers seen by the BBC provide an insight into what the prime minister was saying and discussing with her cabinet colleagues in the days after Hillsborough.

The main issue of discussion contained in these documents was the effect the disaster was going to have on controversial legislation aimed at controlling the behaviour of football fans.

The Football Spectators' Bill was already going through Parliament. The government was determined to continue with it, in order to introduce a national membership scheme for the sport. This would have brought in identity cards for football fans.

According to the conclusions of the first cabinet meeting to take place after the disaster, Mrs Thatcher told her ministers that the situation on crowd safety and hooliganism at football matches "cried out for action".

The government wanted the legislation to be passed in time for the following year's World Cup finals in Italy - to reduce the prospect of crowd trouble. The meeting also discussed using it to bring in any interim recommendations from the Hillsborough Inquiry.

'Gravest matter'

In another meeting with senior cabinet colleagues which took place on the same day, the prime minister said: "To abstain from taking action… would be the gravest possible matter, now that the need for this action had been so conclusively demonstrated."

Image caption Bereaved families have been calling for the release of secret government and police papers about the disaster

Five days later, Home Secretary Douglas Hurd met the man conducting the official inquiry into Hillsborough, Lord Justice Taylor.

A letter written by a civil servant at the Home Office says Mr Hurd told the judge about the government's proposed new timetable to get the football spectators' legislation passed by Parliament.

He then asked Lord Justice Taylor what he would say if the government went ahead with this and then asked "whether he was really quite sure that it was out of the question to form and express a view on the subject of membership cards in the three-and-a-half months… between the start of the inquiry… and the end of August?"

According to the letter, Lord Justice Taylor told him that "this was possible, but he was not confident that it could be achieved".

He said his priority was establishing the facts of what had happened at Hillsborough and could not promise to come up with any recommendations on membership cards in time to fit in with the government's political schedule.

The prime minister was told what had happened in a briefing note from her principal private secretary, who informed her: "Lord Justice Taylor was distinctly unhelpful."

In the end, the government did press ahead with its plans and the law was passed. However, the following year, in his report, Lord Justice Taylor said he had "grave doubts" about the feasibility of football membership cards and "serious misgivings" about the scheme's likely impact on safety. As a result of his concerns, the government dropped the scheme and it was never implemented.