In 1948, the philosopher Bertrand Russell delivered the first series of the BBC's Reith Lectures, on the theme of "Authority and the Individual". Every year since, with the mysterious exception of 1992, a leading thinker has been given the chance to address the world on an issue of broad public concern (see box, page 33). Most have been academics.

Next month, it is the turn of Michael Sandel, Anne T. and Robert M. Bass professor of government at Harvard University, whose lectures, titled "A New Citizenship", will return to territory not far from Russell's by exploring the "prospect for a new politics of the common good".

Sandel is undoubtedly an academic heavyweight, but also a renowned communicator whose undergraduate course on justice has attracted more than 14,000 students and will soon form the basis for a 12-part US TV series. In his Reith Lectures, he plans to address the issues surrounding biotechnology, globalisation, spiritual values in public life and the moral limits of the market. He also relishes the series' "storied tradition of engaging the life of the mind and the public square".

It remains to be seen whether Sandel, in common with a number of past lecturers, will succeed in crystallising contemporary concerns and helping us to find a way through them. For example, Onora O'Neill, who is now president of the British Academy, was widely acclaimed for her 2002 series, "A Question of Trust", which explored how today's methods of ensuring accountability often lead to the erosion of trust in public institutions.

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Although her manner is grandly patrician and she made no concessions to populism, her arguments clearly struck a nerve. Out of a large postbox, her favourite letter came from a 90-year-old blind woman, who said that her nursing home held an informal seminar after each lecture.

It would be hard to find a more striking example of how serious intellectual discussion can make an unexpected impact far beyond the walls of the academy. Anyone seeking to make a case for the value of public intellectuals could do far worse than to start here, but are they also an endangered species, at least in the UK?

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The general picture is not encouraging. Geoffrey Hosking, emeritus professor of Russian history at University College London, whose 1988 Reith Lectures were titled "The Rediscovery of Politics", believes there has been a drastic dumbing down of public discourse over the past two decades.

"The field on which academics might address broad issues in public is getting narrower as a result of developments in the media and in academia," he says. "I am quite gloomy about all this. I fear we are losing the capacity to envisage social processes broadly or to understand their moral implications. Neither academics nor journalists are able to do a proper job in this respect - although there are a few honourable exceptions."

Robin Baker, vice-chancellor of the University of Chichester, concurs. Although he applauds Gordon Brown's 2004 British Council lecture, "Britishness", as a rare example of "a major politician engaging as an intellectual with a heavyweight subject of significance", he believes that the broader intellectual scene in the UK is "an abject place (where) the educated public has been weaned off the sustained scrutiny of thought". Traditional British anti-intellectualism provides an important part of the explanation.

"There is a striking difference between the place of the public intellectual in the UK and what one encounters elsewhere in Western and Central Europe," Baker says. "There, whether in print or broadcast media, the public - or at least enough of them to keep the proprietors of newspapers and television advertisers happy - demand serious intellectual exploration of questions by people who are qualified to provide it. The staking-out of scholarly arguments for public consideration in this country is an activity at the margins."

Yet, beyond this longstanding malaise, Baker points to "other, newer factors that mean the vaguely passable standard of public intellectual discourse we were prepared to accept is being eroded rapidly. The national obsession with talentless celebrity, coupled with an equally powerful - and gleeful - obsession to will even cherished institutions and individuals to fail, presents an unwelcoming backdrop for informed, scholarly and carefully argued discourse.

"There is something gladiatorial about the prevailing culture: not the battle of minds in which the public intellectual thrives, but the popular desire for circus and the lust to witness the destruction of enemies and friends alike."

A gladiatorial culture can give only a particular kind of space to academics, suggests Stanley Fish, professor of law at Florida International University. This is an era of "cameo intellectuals", particularly welcomed by the media if "they hold a position that can be theatrically opposed to that of another well-credentialed professor".

For example, in debates on contentious issues such as conflict in the Middle East, civil liberties versus security, religion versus science or the future of feminism, it is not unusual to pit two or more sharply opposed academics against each other and goad them into slugging it out.

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Television discussion programmes, Fish says, create "a universe populated by people wearing glasses and saying differently extreme things about every subject under the sun". But such debates often generate far more heat than light, and the academics involved can soon lose their public status if the issues they are associated with go out of fashion.

Equally, a lack of support structures can make it difficult for academics to become public intellectuals in a more sustained sense.

Fish once wrote: "If you want to speak to the public, there is no degree to be had, no accepted course of accreditation, no departments of Public Relevance, and above all no network of conferences, journals, fellowships and chaired professorships that give the enterprise a material stability. Were you to wake up one morning and say to yourself, 'I think I'll become a public intellectual', there would be no roadway or sequence of steps whose negotiation would lead to the implementation of your new resolve.

"It is not impossible for someone to be an academic and a public intellectual, it is just that the academic who goes public successfully will have done so not by extending his professional literary skills, but by learning the skills of another profession. If 'public intellectual' is anything, it is a job description, and it is not a job for which academics, as academics, are particularly well qualified."

According to the academic, broadcaster and Times ÖйúAƬ columnist Laurie Taylor, even in the revolutionary 1960s the public still felt a lingering respect for academic authority and expertise that is almost unimaginable today.

Taylor recalls that when Civilisation, the landmark BBC television series written and presented by Sir Kenneth Clark, the art historian, was broadcast in 1969, viewers were still prepared to defer to someone who sounded "aloof, cosmopolitan and sophisticated, whereas we now need signs of fallibility to endear us". He notes that four years later when Jacob Bronowski, the noted mathematician and biologist, explored the history of science and technology in The Ascent of Man, he made no attempt to disguise his "odd voice; he was not matey and made no concessions to his viewers".

None of this applies today. "Most popular purveyors of knowledge in recent years have been inspired amateurs and 'characters' rather than accredited academics," Taylor observes.

Even when genuine scholars such as David Starkey are given a public platform, debate often focuses on their personalities and idiosyncrasies as much as their arguments. Starkey, of course, plays up to this, with his notably "gladiatorial" contributions to debating programmes.

A number of factors explain the relative failure of younger academics to play a high-profile public role in big debates. Intellectual trends such as postmodernism and identity politics have called into question the whole notion of academic (and other professional) expertise.

The rise of the internet has created a new generation of often unaffiliated web intellectuals who can speak directly to the public. A democratic "wisdom of crowds" is celebrated above the prestige attached to long-established professorships. Many of these online orators cannot see why anyone should be given space to lecture us from on high about the state of the nation and "the way we live now".

Another factor is that developments within universities have not always been propitious for the creation of bold, wide-ranging public intellectuals.

"When I started my academic career," Taylor notes, "there were people who could have been described as 'free-floating intellectuals'. They now seem to be imperilled by the constant need to produce research papers."

Interdisciplinary courses and attempts to combat overspecialisation have often foundered, he says, because "academics have chosen to imprison themselves within structures where they are chief warder. They take pleasure in saying other things don't fall within their ambit." He adds that one of his brightest students was once told by her tutor: "Don't bring Freud into psychology."

Yet despite "the intellectual poverty of contemporary television" and the reduction of most political discussion to "well-briefed people mouthing opinions", Taylor believes that these failures "have opened up other arenas for more serious discussion".

"The appetite for public debate is enormous. The Reith Lectures can cash in on that wave of interest for people talking about serious issues," he says.

His own BBC Radio 4 programme, Thinking Allowed, often draws on specialist academic research to demonstrate its unexpectedly wide relevance.

Others have also been interrogating the notion of the public intellectual, whether it is a role that academics can and should adopt - and the kind of spaces they might be able to carve out for themselves.

What are the factors discouraging academics from "going public" and speaking beyond their core areas of expertise?

"There are certainly such pressures within the academy," says Gary Hall, professor of media and performance at Coventry University. "For many people, those associated with the research assessment exercise would be the first that come to mind.

"There is also a certain amount of pressure being placed on academics these days to act as public intellectuals and to communicate their research and ideas to a wider public outside the institutional context in which they work. The argument is that because taxpayers fund their research, academics have an obligation to make it accessible to the public in the form of communicating with journalists, appearing in the media or even writing blogs."

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However, Hall doesn't feel "entirely comfortable with this role. For one thing, it seems to me to risk going along too closely - and somewhat uncritically, especially in view of the financial meltdown and general loss of faith in the idea of unbalanced economic growth - with the current government and research council emphasis on valuing academic research in terms of its potential 'economic and social impact' and ability to be useful to business, industry and the public at large.

"For another, it often results in demands being placed upon academics to be inclusive, and to avoid difficult philosophical or theoretical jargon, in order to communicate better with non-experts and so-called ordinary people.

"But don't academics sometimes need to be difficult, challenging, inaccessible, boring, unproductive, inefficient, uneconomic and non-user-friendly?

"When so much of the rest of contemporary culture places such a high premium on being popular, inclusive, accessible and instrumentally useful, isn't it important that there are at least some places and spaces for exploring ideas that are difficult, challenging and time-consuming to understand, and that are not always justifiable in strictly economic terms?"

All this leaves a number of circles to be squared. Hall notes that academics who wish to play a public role have to negotiate the common British image of the intellectual as "arrogant, pretentious and full of self-importance; someone who tries to give off an air of superiority by using difficult and overly complex language and ideas.

"Paradoxically, to be viewed approvingly as being intellectual in England today, it's better not to be too intellectual at all. So Alain de Botton is generally accepted as a more or less intellectual figure, as he can write clearly on ideas and culture and communicate with a wider public, and even attain the holy grail of popular readership."

Policymakers tend to share this jaundiced view, as was clear from a recent Times ÖйúAƬ feature ("I can't hear you ...", 26 March). Many of them look down on academics as "better at identifying problems ... than at offering solutions". They prefer the advice of think-tanks that can provide "hard evidence by 4 o'clock this afternoon in three bullet points". It seems unlikely that this is an optimal approach to decision-making.

Given that "the UK at the moment contains surprisingly few spaces, other than the university, that are open to intellectual academic work" and that "publishers are barely producing books for third-year undergraduates, let alone research monographs aimed at other scholars", Hall argues for "a need to invent new ways of communicating intellectual academic ideas and research both inside and outside the university".

One option he is pursuing is Internet Protocol Television, which uses computer networks to deliver audiovisual programming - and can be adapted to far more serious purposes than YouTube.

Marquard Smith, principal lecturer in visual culture studies at the University of Westminster, is also looking for new ways to forge a public intellectual profile.

He says: "I think academics feel the urgency of the need to speak, but are wary of speaking too soon. The speed of academic life is in conflict with a soundbite culture. So it is hard for academics to make the kind of interventions they feel they should be making.

"Public dissemination - a phrase I prefer to 'knowledge transfer' - can be seen as watering down. It is hard to be clear while maintaining the complexity of complex ideas, although we also have to do that in our teaching."

Smith is well aware of the obstacles. "The roles once filled by academics are now taken by journalists or heads of pressure groups. Academics have been marginalised to a certain extent and they also marginalise themselves."

Yet there are always fresh options to explore.

"I'm a great fan of learning in public and of intellectual discussion about an important topic that isn't bound by the protocols of academic rules," he says.

For example, Smith is hosting a series of "salons" at the newly reopened Whitechapel Gallery in London, which runs from this month until January 2010 and features academics addressing the theme of hope.

He also points to the existence of similar events at London's British Library, the Institute of Contemporary Arts, the Tate Gallery and the Wellcome Institute, as well as the weekly BBC Two series The Culture Show and "BBC Four documentaries that tend to involve academics behind the scenes and as talking heads".

Another good stage for academics and non-academics, he adds, is Resonance FM, a radio station that for the past seven years has sought "to make London's airwaves available to the widest possible range of practitioners of contemporary art".

Even in his own fairly specialist field, Smith argues, there are many outlets for academics to get out and address whoever is interested about the big themes of the day. And, despite the challenges, scholars need to grab the opportunities and build on them.

He says: "I would like to see many different kinds of media giving academics a chance to put their ideas across. What people get to see is a very small sample. In the main, academics are an interesting bunch with interesting things to say, and they need to find new ways of getting this across."

A GREAT BRITISH INSTITUTION

The Reith Lecture series is a great British institution, a continuing tribute to the BBC's founding ideals of public-service broadcasting - and an accurate barometer of the changing ideal of the public intellectual. For the lectures' 40th anniversary last year, Laurie Taylor presented a two-part radio series about their history.

He reported the startlingly prophetic eloquence of the 1969 lecturer, Frank Fraser Darling, the English ecologist, who warned that the greenhouse effect would lead to rising oceans and melting polar icecaps.

He also noted a series of fierce controversies: in 1978, Edward Norman, a conservative philosopher and ordained minister, attacked the modishness and happy-clappy tendencies of the Church of England, which he later left. The following year, Ali Mazrui, today based at the State University of New York, Binghamton, provoked equal outrage with his series, "The African Condition", in which he argued that violence had been necessary to end white rule on the continent and that nuclear proliferation should be extended to African states.

In 1993, Edward Said offered a powerful portrait (or self-portrait) of the politically engaged public intellectual in the Noam Chomsky mould, one committed to speaking the truth to power and unmasking official lies.

Along with composer Alexander Goehr (1987), Jonathan Sacks, the Chief Rabbi of the UK (1990), architect Richard Rogers (1995), novelist Wole Soyinka (2004) and conductor Daniel Barenboim (2006), not to mention a guest appear-ance by the Prince of Wales (2000), the Reith Lectures have showcased many leading academics. Some are now largely forgotten, but many have stood the test of time.

The 1966 lecturer, J.K. Galbraith, has recently returned to favour as a guide to help us find a way through the economic crisis. Even Bertrand Russell, although much mocked for his political engagements towards the end of his life, remains a huge presence in the philosophy section of bookshops almost 40 years after his death.

The lectures have offered gripping, accessible overviews of emerging fields such as neuroscience, genetics and geriatrics. And with themes such as "The World and the West", "War in Our World", "Minds, Brains and Science" and even "The Future of Man", no one could accuse them of intellectual timidity.

But although the comically plummy voices have disappeared, the lectures have always struggled to trawl beyond the pool of white, male, Anglo-American academics. There was not a single female Reith Lecturer between Margery Perham on "The Colonial Reckon-ing" in 1961 and Marina Warner, now professor of literature, film and theatre studies at the University of Essex, on "Managing Monsters" in 1994. Warner had to put up with a good deal of abuse.

Some of the stock adjectives that always go with "intellectual" in England include "French", "emigre", "head-in-the-clouds" and "unworldly". Partly because the Reith Lectures require native fluency in English, only one Frenchman has been offered the podium, Jacques Darras in 1989. The great generation of refugees from Central Europe was represented by art historians Nikolaus Pevsner (1955) and Edgar Wind (1960).

Talent from abroad has been crucial behind the scenes. In the 1970s, as some within the BBC feared that the lectures were becoming an anachronism, they were revivified by George Fischer, the head of talks and documentaries, and a team of Central European emigres committed to the highest intellectual standards. Like much in British cultural life, the essential stimulus was provided by outsiders.

It is a familiar complaint that the British don't treat their intellec-tuals with respect. But since the grass is always greener, people in other countries offer similar gripes and claim that the situation is better here. Indeed, those making this case often cite the Reith Lectures themselves.

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