The public intellectual is an increasingly rare species. I don't mean academic celebrities with their television series and regular op-ed columns. Public intellectuals are men or women of considerable intellectual attainment, usually professors at the older universities, who are also committed to public service where their wisdom and experience are admired and their judgement sought. Such figures need not be politically neutral; indeed, they may fall out with political leaders who come to dislike their blunt advice, perhaps given in private and public.

In this country, John Maynard Keynes was a public intellectual, admired at Cambridge as more than an economist – he made King’s College rich and encouraged the arts in many forms. On both sides of the Atlantic his economic advice was incorporated in the highest affairs of state, while in