You write:

'As you know, journalists whose politics are broadly in line with yours, and who are hostile to big business and the corporate domination of politics and the media, have become, following your attempts to engage with them, not your allies but your sworn enemies.'

Specifically, you focus on 'the issue of bombardment':

'Bombarding a very busy person with the same thing, over and over, is an effective formula for infuriating them and making them think "to hell with the lot of you!".

But cast your mind back to July 2004 when you slammed the media for 'falsehoods' prior to the invasion of Iraq that were 'massive and consequential', adding: 'it is hard to see how Britain could have gone to war if the press had done its job'. You bravely included the Guardian and Observer in your criticism, and asked: 'So who will hold the newspapers to account?'

Your conclusion:

'It seems that the only possible answer is you. You, the readers, must take us to task if we mislead you. Pressure groups should be bombarding us with calls and emails - you'd be amazed by the difference it makes.'

An example followed when you wrote an article in the Guardian on the problem of advertising and climate change after being 'challenged by the editors of a website called Medialens'.

Eight years ago, we would be 'amazed' at what a positive difference 'bombarding' makes. Now we'd be amazed at how counter-productive it is. This is another reversal of opinion reminiscent of your dramatic conversion to nuclear power.

The big addition to the Guardian over the last year, of course, has been the fine American journalist Glenn Greenwald. Last year, we challenged him on his willingness to criticise the Guardian. He replied in his usual forthright manner, describing our argument as 'moronic'. So far so good for your hypothesis that we do a great job of alienating like-minded journalists. But Greenwald told another Twitter user (copying to us):

'I don't mind - I actually like - debates like these. They're healthy among allies. I'm not interpreting it as rudeness.'

Last month we responded to news that Greenwald had joined the Guardian by challenging this tweet from him:

'Would NPR [National Public Radio] ever do a panel called: "Iran perspectives on Israel," with 3 advocates of the Iranian govt and nobody else?'

We wrote: 'Would the Guardian ever do a panel called: "Herman/Chomsky perspectives on the corporate media"?'

You will recognise this as the kind of annoying challenge we've been sending you for years. Again, consider Greenwald's message to us just days later after David Aaronovitch of The Times described us as 'Twitter dickheads' who thought 'killing US embassy staff is cool':

'You are really deeper in the heads of the British establishment-serving commentariat than anyone else - congrats.'

Greenwald went on to condemn Aaronovitch's charge as a 'lie' and a 'wretched falsehood'. He defended us against Aaronovitch, Oliver Kamm (The Times), Nick Cohen (Observer) and other hard-right 'liberal-left' commentators.

A concerned Twitter user then warned Greenwald about us, essentially making your point:

'You should look at ML's targets since 2001. Very revealing. So much time spent on [Seumas] Milne, Monbiot, Nick Davies, IBC [Iraq Body Count], etc.'

But Greenwald understands what we're doing and is not easily swayed. He replied: 'Journalists with a large corporate platform, and who are seen as liberal commentators, wield lots of influence.' And added of us: 'They've criticized me before, too - sometimes harshly - that doesn't make me think they're evil.'

The Curious Case Of Sweden's Fria Magazine

This confirms many years of experience. Obviously no-one likes criticism, particularly prominent journalists accustomed to warm applause from progressives. But, to their credit, we've found that many of the better journalists are able to keep their heads. They judge us by the rationality of our arguments and by the value of what we're saying; they don't just write us off or lash out.

A few years ago, we wrote a media alert with the harsh but irresistible title, 'Debunking Buncombe', inviting readers to contact the eponymous Andy Buncombe of the Independent. Despite the ensuing 'bombardment', Buncombe has since cited our work in his newspaper and often retweets our media alerts on Twitter, even when they criticise the Independent. For example:

'@MediaLens has some useful thoughts on the coverage of Gaddafi's killing.'

As usual when a high-profile journalist mentions us positively (or indeed mentions us at all), Oliver Kamm worked hard to scare Buncombe off with hair-raising tales of our involvement with 'genocide denial'. Buncombe's response:

'As for MediaLens, while I certainly don't agree with everything they say, I've never read anything they've produced that would support your very strident allegation.'

You, by contrast, are Kamm's great triumph - you swallowed his smears hook, line and libel, echoing them in a Guardian column that alienated a huge swath of the Left. You even gave one of your blog entries the title: 'Media Cleanse', writing of how 'a group which claims to defend human rights turned into an apologist for genocidaires and ethnic cleansers'.

We challenged Buncombe exactly as we challenged you, but he took it upon himself to publicly defend us against a hard-right fanatic. The risk, as he must surely have been aware, was that he would be labelled 'one of them'. Or as Aaronovitch told Greenwald: 'Your funeral.'

A journalist who knows better than most what it's like to be 'bombarded' by Media Lens is Peter Barron, who was editor of the BBC's Newsnight programme at a time when we sent dozens of media alerts criticising BBC performance on Iraq in 2002-2003. Barron commented on the BBC website: 'after every controversial episode I get hundreds of e-mails from sometimes less-than-polite hommes engages'.

Despite this, he wrote:

'Another organisation that tries to influence our running orders is Medialens... They prolifically let us know what they think of our coverage… In fact I rather like them. David Cromwell and David Edwards, who run the site, are unfailingly polite, their points are well-argued and sometimes they're plain right.'

Starkly contradicting your 2012, although not your 2004, analysis, Barron added:

'Are these unsolicited interventions helpful or unhelpful? The former, I think, as long as we read them with eyes wide open. You might argue that it would be purer to ignore the pressure from all quarters, but I think lobbying can actually improve our journalism, as long as it's not corrupt, that access to the editors of programmes is equally available to everyone (via e-mail it is) and that we question everything we're told.'

Barron noted that when the second Lancet study on the death toll in Iraq was published in 2006, he received a wave of emails from 'anti-war groups' urging him to cover the story. But he then received 'a second wave of e-mails. Not really suggesting we don't do the story, but urging that, if we do, to note that even the authors claim that it is of "limited precision". Don't be bullied by the anti-war lobby'.

One might wonder who these 'second wave' emailers were and what their motive was. The question naturally arises: are we to leave the field to pro-war lobbyists often centrally organised and funded, with roots in corporate-sponsored think tanks and state-sponsored agencies, with journalists of the hard-right working diligently to advance their agenda? While we are two writers solely dependent on the donations of individual readers (none of them wealthy philanthropists), these flak groups have huge resources. On Twitter, we agreed not to put your name at the bottom of any more alerts because doing so was driving you 'bananas'. You shouldn't expect the same understanding from the pro-war lobby.

Former New Statesman editor, Peter Wilby, whose email featured in our 'Suggested Action' section even when he was publishing David Edwards' articles on a regular basis for two years, subsequently reviewed one of our books, Guardians of Power: The Myth of the Liberal Media, in the New Statesman:

'All journalists should read it, because the Davids make a case that demands to be answered.'

As a final example, we've had intense debates with another well-known journalist at the Guardian whose email address has appeared many times in our alerts. Exactly contradicting your 2012 hypothesis, in April 2011 this journalist recommended us to the editor-in-chief of Sweden's Fria magazine, Madelene Axelsson, who then interviewed us about our work. She wrote to us:

'Well you know he was in fact the one who directed me to you. He spoke very highly of your work and said more than one time what important work you do.' (Email, Madelene Axelsson to David Edwards, April 26, 2011)

The 'he' in question, George, as you know, was you!

Power Concedes Nothing

You write:

'I do not love receiving scores of almost identical messages from people who sound as if they haven't thought through an issue for themselves, but are parroting a line - often the exact words - formulated by someone else.'

No-one has read more of these emails than we have over the years and we wholly reject your description. By the very nature of what we're doing we tend to attract non-conformists. We are anti-authoritarian, anti-conformity, anti-parroted thinking. In our experience, the vast majority of emails sent to journalists are of a very high standard - restrained, thoughtful, serious. We suspect it is precisely this that annoys you. It is easy to dismiss idiotic abuse. It is much harder to deal with intelligent, accurate criticism.

You write:

'I've stayed with the Guardian because I believe it provides the best opportunity I have at the moment to change the way people see the world.'

That's fine - you sincerely believe that - but we fear you may have suffered from the process of corporate assimilation you warned against many years ago:

'It is an exceptional person who emerges from this process with her aims and ideals intact. Indeed it is an exceptional person who emerges from this process at all. What the corporate or institutional world wants you to do is the opposite of what you want to do. It wants a reliable tool, someone who can think, but not for herself: who can think instead for the institution. You can do what you believe only if that belief happens to coincide with the aims of the corporation, not just once, but consistently, across the years (it is a source of wonder to me how many people's beliefs just happen to match the demands of institutional power, however those demands may twist and turn, after they've been in the company for a year or two).'

It is 'a source of wonder' to us that your perceptions of the Guardian 'just happen to match the demands of institutional power'. Thus, you write: 'the bulk of the Guardian's coverage of these issues has presented fierce challenges to the Murdoch empire, the banks, the government's cuts, its privatisation and outsourcing, the war with Iraq, the drone war in Pakistan and a host of other topics of interest to you'.

Fierce challenges? Not true, as we'll see below. For now, consider that in 2010, you and a host of other liberals signed a letter published in the Guardian titled 'Lib Dems are the party of progress':

'The Liberal Democrats are today's change-makers. They have already changed the election; next they could drive fundamental change in our political and economic landscape.'

In your booklet, An Activist's Guide to Exploiting the Media, you wrote:

'We're genuine people, not hired hands defending a corporate or institutional position.' (George Monbiot, An Activist's Guide to Exploiting the Media, Bookmarks Publications Ltd, London, 2001)

We wonder how the younger George Monbiot would have viewed your defence of the Guardian now.

You told us on Twitter that while comments posted about your work on the Comment is Free website can be annoying, it is somehow worse to have them appear in your inbox. But think what you're saying, George! Some two million people are lying dead in Iraq as a result of Western war, sanctions and yet more war - some of the most barbaric crimes of modern times. While catastrophic climate change looms, the political and media silence is deafening. Authentic democratic choice has dissolved to nothing. And we need only remember the struggles of the past when civil rights, peace and other activists organised, mobilised - and even fought and died - to achieve progressive change. And yet, from the comfort of your salaried position at the Guardian, you are publicly protesting a tiny website urging people to send polite emails! In the last five years, your email address has appeared seven times at the bottom of our media alerts - a little more than once a year. How complacent and comfortable have you become? The abolitionist Frederick Douglass said:

'Those who profess to favor freedom and yet deprecate agitation, are men who want crops without plowing up the ground… Power concedes nothing without a demand. It never did and it never will.' (Frederick Douglass, 1857. Cited, Howard Zinn, A People's History of the United States 1492-Present, Perennial Classics edition, HarperCollins, 1999, p.183)

Moral Complexity

Let's look in more detail at some of your claims. You write that the issues surrounding 'the matter of whether NATO support for the rebels opposing Gaddafi was a good or a bad thing, are morally complex. I still don't know where I stand on that (which is why I haven't written about it), because I can see compelling moral arguments on both sides.'

The West clearly exploited UN Resolution 1973 to illegally pursue regime change in Libya. As Seumas Milne noted, the cost was paid in tens of thousands of Libyan lives. Libya is now in a state of violent chaos with numerous armed militia running a lawless country awash with weapons. If we care about international law, Libyan lives and resisting our government's violence, there is really no moral complexity.

Last year you tweeted: 'I find myself seriously torn by it. I feel the right thing has been happening for all the wrong reasons.'

In fact terrible things were happening, supported by Nato - massacres, ethnic cleansing, widespread destruction - for all the wrong reasons.

You write that we 'often seem to ascribe to people the worst of all possible motives':

'I've noticed over the years that when a journalist working for the Guardian disagrees with your line, you have characterised them as a corporate stooge.'

This is simply false. We have never referred to any journalist in any alert as 'a corporate stooge'. One of the really fascinating issues for us - something we have thought about and discussed for many years - is the question of how it is that intelligent, well-intentioned people can unwittingly come to conform to destructive power. You make no concessions to this kind of discussion or the reality behind it in your letter to us. The fact is that media professionals do conform to the needs of their employers. Coincidentally, former Guardian journalist Jonathan Cook emailed us two weeks ago to discuss just this issue. He wrote:

'I've always loved the metaphor you have in Newspeak [our 2009 book] of the great shoals of fish that move and turn in absolute synchronicity, even though it is impossible to identify a leader or a hand directing them. That is exactly how it felt when I was at the Guardian. We all knew precisely what was expected of each of us and yet one couldn't identify a single person, not even the Editor, who was guiding or directing us. We simply knew what we should do. If we gave it a label, it was the "ethos" of the place. That's why you were at the Guardian, after all. You either accepted it willingly as your own ethos or left. It's another way of understanding Chomsky's filters: the reason senior journalists always say no one ever told them what to write etc. No, we didn't need to be told. We were Guardian worker bees or drones: we had the Guardian "ethos". Those who didn't were picked off, like a straggler fish caught by a shark.' (Jonathan Cook, email to Media Lens, October 25, 2012)

This is the kind of honest, thoughtful, self-critical analysis that fascinates us; not the crude demonisation of 'stooges' and 'quislings'.

Missing Frameworks Of Understanding

You write:

'The third issue is what I perceive as confirmation bias: that you appear to have begun with a conclusion - that the Guardian conforms to the Herman and Chomsky propaganda model - then sought evidence to support it.'

In fact, like most people, when we first read the Guardian, we assumed it was indeed an open, independent window on the world. It was only after the likes of Noam Chomsky and Edward Herman opened our eyes that we began to question that view. You write:

'I challenge you to conduct a comprehensive assessment of the paper's coverage of climate change over the past few years…'

The US media analyst David Peterson commented on this point:

'George Monbiot is trying to dissuade Media Lens from even bothering to counter his statement and his general belief about the Guardian - Observer's performance as a news organization by raising the bar of evidence sufficiently high (i.e., exhaustive case studies of Guardian - Observer performance on a variety of important topics) that he expects you not to take him up on his challenge.

'The readership of his website will find his letter to you (or be directed to it via Twitter), see that you have not just turned-on-a-dime and in short order produced, say, ten case-studies of sufficient scope as to meet his criteria, and come away feeling that you cannot answer him.' (Email to Media Lens, October 28, 2012)

Sadly, that does appear to be what you had in mind. In fact, we have extensively followed and analysed Guardian coverage on climate change over many years (see our Post Script, which provides a small sample of this work. You quoted not a single word from our alerts or books in support of your arguments).

Paired examples can be used to demonstrate bias in quite a simple way. In May, we noted that the media had instantly decided that Syria's president, Bashar Assad, had been personally responsible for the massacre of women and children in Houla. Within hours of the massacre being reported, a cartoon in the Guardian depicted Assad with his mouth and face smeared with blood. We recalled that, in March, a US soldier had shot dead 16 Afghan civilians, nine of them children. We asked what kind of evidence the media would have required before finding Barack Obama (and even Michelle Obama) personally responsible for this or any other massacre. It is inconceivable that the Guardian would have published a comparable cartoon with Obama's face smeared with blood so soon after a massacre had been reported.

This was a small but significant example of how the media, including the Guardian, consistently treat 'our' leaders, 'our' violence, 'our' crimes, one way, and those of the Official Enemy another way. This was not hard science, but it was common sense. By the way, compare our actual purpose with the absurd suggestion that we were apologising for Assad's violence and tyranny, as Kamm and others have claimed.

We have also provided comprehensive assessments of Guardian and Observer reporting. In 2003, we found that the number of articles mentioning Iraq in January of that year in the two papers totalled 760. These are some of the mentions we found:

Iraq and George Bush, 283 mentions. Iraq and Tony Blair, 292. Iraq and Jack Straw, 79. Iraq and Colin Powell, 67. Iraq and Donald Rumsfeld, 40. Iraq and Dick Cheney, 17. Iraq and Richard Perle, 3.

We also found these mentions for major anti-war voices:

Iraq and Tony Benn, 11 mentions. Iraq and George Galloway, 10. Iraq and Harold Pinter, 5. Iraq and Scott Ritter, 4. Iraq and Noam Chomsky, 4. Iraq and John Pilger, 2. Iraq and Denis Halliday, 0. Iraq and Hans von Sponeck, 0. Iraq and Milan Rai, 0.

So these leading voices for peace at a time of massive public opposition to war totalled 36 out of 760 mentions of Iraq, less than Donald Rumsfeld alone received. Again, this was not hard science, but it did provide serious evidence of Guardian/Observer opinion bias in favour of warmongers. We found a similar pattern of coverage in 2002. See our Post Script for further key examples.

You set a very low bar in triumphantly pointing to the Guardian's better coverage of climate science compared with the likes of the Telegraph, Express and the execrable Mail. This is hardly a badge of honour. The veteran, award-winning climate campaigner Aubrey Meyer is now so unimpressed by the Guardian that he told us: 'I stopped reading the paper because the coverage became so trivial.' (Email to Media Lens, October 29, 2012)

On climate, you write: 'I think you'll discover that far from doing so, the Guardian has mounted a fierce and sustained challenge to the corporate-friendly coverage of this issue in the media…'

A deeper problem with the Guardian's performance on climate change is that the honest frameworks of understanding required to generate radical change are simply ignored or side-lined throughout the newspaper. For example, it should be a part of basic awareness that corporations, including your employer, are locked into a biocidal logic demanding maximised revenues in minimum time at minimum (corporate) cost. Front and centre of Guardian reporting on climate should be the fact that corporations are legally obliged to maximise profits for shareholders; that it is in fact illegal for corporations to prioritise the welfare of people and planet above private profit. The Guardian should be presenting the state-corporate system as fundamentally pathological. This it manifestly does not do, even when challenged to do so (specifically economics editor Larry Elliott and environment editor John Vidal: see Post Script).

The long and spectacular history of corporate power organising to manipulate culture, economics and politics should also be a central theme in comment pieces and editorials. Your newspaper barely skims the surface of these issues. Instead, it endlessly peddles the party political charade as meaningful. It persuades readers to find hope in a Blair (even after Iraq!) and an Obama, when it should be exposing the biocidal nature of the entire system of which they are a part, and calling for grassroots change through massive public mobilisation. As we and others have pointed out, voters are free to choose from two or three political 'choices' that have in reality all been pre-selected by established power. A significant proportion of the Guardian's output is devoted to selling this fraudulent choice as a positive exercise in democracy.

Similar non-issues for the Guardian are the true nature and role of the corporate media, and the part it plays in normalising irresponsible consumption and in stifling awareness of the threat of climate change. The Guardian has never published a serious structural analysis explaining why a corporate media system cannot be trusted to report honestly on a world dominated by corporate power. How could it? There are occasional mentions of isolated aspects of the problem - the role of advertisers, Murdochian monopolies and so on - but the basic structure of the system is just not up for discussion. Your idea that the Guardian is a 'fierce' contributor to action on climate change when it is dependent on advertisers for 60 per cent of its revenues is darkly humorous, nothing more.

We could go on - our comprehensive assessments, over many years, reveal that these basic frameworks are ignored in favour of 'left-liberal' 'optimism' and 'pragmatism'. There is no meaningful discussion of structural change because corporate media like the Guardian are literally in the business of maintaining the status quo. It is remarkable that this is not obvious to you.

As well as the above and the Post Script, you can read responses from Jonathan Cook and David Peterson here. We twice emailed Glenn Greenwald asking for his thoughts on your criticism - we received no reply.

Best wishes

David Edwards and David Cromwell

Update November 6, 2012

In the first paragraph, we originally wrote:

'It's good to know that your email is intended in a "friendly and constructive spirit", and not as a follow-up to something you wrote of us three weeks earlier: "I could spend my life unpicking their falsehoods. Perhaps I should, cos no one else is."

George Monbiot has clarified that he was not in fact referring to us.

We are happy to correct this misunderstanding.