a rift between David Cameron and his top civil servant became public

This week a rift between David Cameron and his top civil servant became public. Sir Gus O’Donnell, the Cabinet Secretary, was apparently deeply unhappy about the Prime Minister’s recent speech fingering the bureaucrats of Whitehall among “the enemies of enterprise”.
Strains in relations between Number 10 and the Cabinet Office next door are nothing new. For the cabinet secretary of the day is the most powerful unelected member of the government; he is the real-life Sir Humphrey from Yes, Prime Minister, who pulls the invisible strings across the whole of Whitehall. And cabinet secretaries tend to stay in office when a prime minister moves on: there have been only 10 of them since the Cabinet Office was formed nearly a century ago, but there have been three times that many governments.
Unlike the prime minister, the top mandarin is allowed to see all the papers of previous governments. In Whitehall, where knowledge is power, the Cabinet Secretary is the person who knows most of all. He is the chief policy adviser and father confessor to the prime minister. He sits next to the prime minister at all meetings of the Cabinet and its top committees. So the current Cabinet Secretary, Sir Gus O’Donnell, who is on his third PM, knows more secrets about Tony Blair, Gordon Brown and David Cameron than anyone else in the country.
Sir Gus gave Mr Cameron the traditional first briefing by the Cabinet Secretary after he entered Number 10. “There are various nuclear and intelligence issues which new prime ministers need to be briefed on very quickly,” Sir Gus says. “And one of the things the cabinet secretary has to do is to juggle those first 24 hours in managing this process of getting the urgent and important done.”
After that first briefing about some of the stark realities of power, prime ministers are never quite the same again. Tony Blair’s ex-chief of staff Jonathan Powell takes a decidedly realpolitik view of what the cabinet secretary is seeking to do: “What’s happening there is a wrestle for power. The cabinet secretary is trying to capture the prime minister by overawing him about the job he is taking on.”