Lord Hennessy has derided the government's plans for civil service reform as a "hissy fit".
The crossbench peer and professor of contemporary British history defended Whitehall's current structure as he gave evidence to the Public Administration Committee on 8 January 2013.
In December 2012, Cabinet Office Minister Francis Maude outlined plans to give ministers a greater role in appointing permanent secretaries.
But Lord Hennessy said the civil service should be "a republic of the intellect" and "people should be placed on what they know, not what they believe".
Historians Patrick Wood from Manchester University and Professor Chris Hood from Oxford University also gave evidence.
In the second part of the session, MPs took evidence from think tanks Policy Exchange, the Institute for Government and Reform.
Sean Worth from Policy Exchange defended the view that senior figures from the private sector should be brought in to the civil service on high pay to perform top roles.
"I despair at the idea that the civil service is somehow special. In every other sector - business, charities - you hire outside yourself to make big changes," Mr Worth argued.
Andrew Haldenby from Reform said, "If there was confidence in the civil service we wouldn't be having this discussion."
The session was the first stage in the committee's inquiry examining the government's proposals for reforming Whitehall.