Former Cabinet Secretary Lord Butler has called on Gordon Brown to restore some of parliament's power when he takes over as prime minister.
Too much 'flim-flam' in government says Lord Butler
Lord Butler told the Hay festival in Powys there should be "more substance to the government and less flim-flam".
He said he had seen the powers of the Cabinet steadily decrease.
Lord Butler also criticised standards of government white papers, saying some had read like "sales manifestos" and been full of soundbites.
He said Tony Blair's successor at No 10 should restore Cabinet government, and papers should be properly circulated to ministers in order that they can make informed decisions.
Lord Butler served as Cabinet Secretary for 10 years until 1998 and led the inquiry into the intelligence which took Britain into the Iraq war.
He said he had served under five prime ministers - Edward Heath, Harold Wilson, Margaret Thatcher, John Major, and finally under Mr Blair for an eight month period.
The only decision the Cabinet made collectively during the time under Mr Blair, he told the festival audience, was about the Millennium Dome, and that was when the prime minister was absent at a memorial service, and the matter was steered through by his deputy John Prescott.
He acknowledged that the nature of governance has gradually weakened, not just under New Labour but since the Second World War.
Lord Butler, 69, said Lady Thatcher ran her Cabinet by "haranguing, dominating and putting the fear of God into people" while her successor Sir John Major ran his "like the captain of a team".
He welcomed the fact that Gordon Brown has already indicated he will look at reform in this area and said if parliament did not put government under close scrutiny, then government got lazy.
He said the system of decison making in government was "faulty", adding he did not think the public was "swayed" by tomorrow's hedlines but politicians think they are.
What matters in the long term, he said, were good policies.
Lord Butler also criticised the standard of government white papers, saying some have read like "sales manifestos" and been full of soundbites, and said select committees in parliament should be made more "effective".