Expressing concern over the safety of Pakistan's nuclear arsenal, a former senior intelligence officer has raised serious doubts about the control of civilian authority over the nuclear chain of command. Observing that Pakistan witnessed four coups in 60 years, he said its nuclear weapons programme has been the "sole preserve of the army" and there were "serious doubts" persisting within Pak about the level of knowledge in the civilian leadership about the critical aspects of nuclear policy.  In his latest book, Lt Col RSN Singh quoted slain leader Benazir Bhutto as saying that she came to know more about Pakistan's nuclear programme from the CIA rather than her own army. Similarly, any notion about any degree of civilian control was dispelled when Nawaz Sharif was deposed as Prime Minister by Pervez Musharraf.  "No Premier could have tamely handed over the nuclear key -- if by chance he had it -- to a General who had just ousted him in a coup," the former officer of the Research and Analysis Wing (R&AW) of the Cabinet Secretariat said, adding that any hope about civilian control of Pakistan's nuclear arsenal was dashed by Musharraf's coup. "Pakistan's polity is characterised by disorderly transfer of power, with serious implications for the viability of any nuclear chain of command," he said in the book 'The Military Factor in Pakistan'.  The book, published by Lancers and brought out by the Observer Research Foundation, was released today by former Indian army chief Gen V N Sharma.