In the book "Ayodhya 6 December 1992" (Penguin Vikings) that appeared posthumously, Rao said the Kalyan Singh government had given assurances to the National Integration Council that the disputed structure would be protected.
The 16th century Babri mosque believed by radical Hindus to be built on the birthplace of Ram was demolished on Dec 6, 1992. The demolition led to riots in many parts of the country.
Rao said the state government had also told the Supreme Court that the "kar seva (voluntary service)" for construction of the temple would be symbolic and there would be no construction activity on the acquired land.
"However, when seen in the light of the actual course of events and the conflicting statements from other representatives of the VHP and Sangh Parivar, these assurances seemed designed more to avoid giving cause to the central government or the courts for action against the state government," he said.
The book, written in the mid-1990s after Rao stepped down as prime minister, was published posthumously according to his wishes. Rao died in December 2004.
Rao said the state government adopted a "dilly-dallying policy" on using central paramilitary forces sent to Faizabad and Ayodhya. The state government did not give "consent" for use of paramilitary forces - a provision mandated by the constitution under India's federal structure - even after vandalism erupted at the disputed site, he said in parliament.
"There was no action.. the crowds carried out the demolition of the structure without let or hindrance," Rao said.
He said the state police moved away as the kar sevaks scaled barricades and clambered on to the domes of the mosque where saffron flags were hoisted. "Then began a frenzied demolition with shovels, iron rods and pickaxes.
While this was going on, the local authorities and the police appeared to be standing as mute spectators. This dismal picture of inaction and dereliction of duty was because of orders from the chief minister not to use force."
Rao said there was no lapse whatsoever on the part of central government. "If the state government had at least made use of the central forces in time and meaningfully, the Babri structure could certainly have been saved Dec 6, 1992. The UP government and the BJP, the party of the state government, would have to be held completely responsible for this wanton vandalism perpetrated on the secular credentials of the nation on that unfortunate day," Rao said in his book that reproduced his parliament speeches of the time as well as his official correspondence with the chief minister and others on the issue.
Rao said in the book that he had made efforts to find an amicable solution to Ramjanambhoomi-Babri Masjid dispute.
"However, the VHP and RSS had decided to wreck the negotiations and the BJP, of course, connived all the way."
Rao also conveyed his unhappiness over being blamed by some leaders in his party for the inability of the central government to prevent the demolition.
He said his colleagues were guided by political and vote-catching considerations and "had already made up their mind that one person was to be made historically responsible for the tragedy, in case the the issue ended up in tragedy".
"...so they were playing either for success, or an alibi through a scapegoat in case of failure! It was a perfect strategy. They could loudly proclaim later that the Muslim vote did not come to the Congress after the demolition of Babri masjid solely because of me. It remains to be seen whether the future will vindicate me in this regard; if it does, I shall, of course, feel happy," Rao said.