It’s only when I’m settled down at a pavement table outside Café Nero that I realise this must be the first time in my 30 years in London that I’ve ever knowingly been to Portobello Road. Perhaps I’ve been deterred by all those tourist recommendations. Or perhaps it was the irritating way it’s always referred to as the Portobello Road. (Whoever heard of the Euston Road or the Tottenham Court Road?).

But where else on earth could I expect to find Richard Curtis? He’s now more closely associated with the area than Nelson with Trafalgar Square. He doesn’t just make films about Notting Hill and the Portobello Road; he works five hundred yards away from where I’m sitting and proudly calls his offices Portobello Studios.

I’ve a good half hour to spare. A necessary precaution. It took the best part of three months to set up this interview and after all that arranging and re-arranging I’m certainly not going to risk being rejected for missing my 4.30 deadline. That’s why my mobile phone is off. No chance now that anyone can text through a last second cancellation because Richard has had to suddenly dash off to the States or pop downtown to pick up another lifetime award.

I’m joined at the next table by two elderly rastas. They don’t have a coffee between them. But they relax into their seats with all the relish of people sinking into their domestic armchairs. Minutes later the smell of my dipping biscuit is augmented by drifting clouds of hash. Perhaps I could get to like this place.

This would be a good time to check my questions. But it seems more important to concentrate on getting in the right frame of mind. For even though I’m intrigued by the idea of talking to Curtis I’m well aware that few of my friends share my curiosity. One or two openly wondered why I should be even mildly interested in someone who has made such a powder puff contribution to film and television. Had I seen Love Actually? Another old rationalist friend went into a lengthy trope about the horrors of Richard’s 14-year old charitable venture, Comic Relief, and the manner in which it simultaneously contrived to sentimentalise the horrors of African poverty and revive the fading careers of second-rate celebrities.

I’d no great problem waving away the artistic objections. I thoroughly enjoyed Four Weddings and a Funeral. It was funnier and darker and far more ambiguous about how happiness might be obtained than many of its critics allowed. Of course Notting Hill was little more than a remake but in these days of Spiderman 3 and Die Hard 4, can we really become pious about someone cashing in on a successful formula? And no one could possibly doubt the contribution that Curtis has made to television. What a roll call of credits! Not the Nine O’clock News, Blackadder, The Vicar of Dibley, Mr Bean. I knew without bothering to check that even my most cynical friends had spent a good few hours of their lives lying back and chortling with delight at one or more of those offerings.

I nodded goodbye to my slumped Café Nero friends and made my way up the road to Portobello Studios. This isn’t my first meeting with Curtis. We’ve run into each other a couple of times before at Red Nose events. He hasn’t changed. Even though his well-developed business acumen must by now have earned him enough cash to buy up most of west London, he still manages in conversation to exude all the innocent eagerness of a child unpacking a first Christmas stocking. You can’t imagine that this man ever finds it hard to get out of bed in the morning or feels the need for a handful of pills or a large slug of alcohol to tide him over a bad day at the office. He is, and I think I mean this as a compliment, the only person I’ve ever met who seems to have taken to heart the old hippy cliché that tomorrow is the first day of the rest of your life.

But, of course, it is just this niceness, this unglazed optimism, that so riles his critics. In an age where public personalities are only promoted by confessions of inner torment or revelations of aberrant behaviour, it is almost an insult to the cultural ethos of the nation to have a public figure with about as much evident angst as Francis of Assisi.

I tell myself that he can’t possibly be as pleased to see me as his face and tone suggest. After all, he only has to look at me to know that I must have the sort of friends who would not regard his life and work as wholly admirable. I need to get a little nasty.

“You once spoke about what you called ‘a critical fallacy’ – the prevalent cultural idea that anything that is harsh or violent is inherently true to life, whereas anything that is warm and positive is inherently false. Isn’t that a bit fluffy? A bit Easter bunny?”

Have I already gone too far? Curtis doesn’t do interviews. He says he doesn’t like to talk about comedy because that only makes it boring, and he doesn’t speak about his charity work because that doesn’t raise a single penny for the cause. And now, a minute after warmly welcoming me into his busy office, he’s being asked to defend his life philosophy. But he doesn’t hesitate.

“I really do believe that there is a tremendous amount of optimism, goodness and love in the world and that it is under-represented. But if you do feel it and experience it then you should write about it. The dark side is always dominant. What is the nastiest thing that has happened to me? What is the worst thing I can imagine happening to me? What were the worst three days of my life? Ah. I shall write about that. It is a sort of sentimental conspiracy about violence. You write a play about a soldier going AWOL and stabbing a single mother and they say it is a searing indictment of modern British society. It has never happened once in my entire life. Whereas you write a play about a guy falling in love with a girl which happens a million times a day in every corner of the world and it’s called blazingly unrealistic sentimental rubbish. It has always been that way. Nobody has really written anything intelligent about Shakespeare’s comedies. People prefer to write about tragedies because they can’t get to the bottom of happiness or comedy.”

I tell him that this reminds me of a recent article in Prospect by Julian Gough in which he wondered why so many contemporary novels were tragedies. Why, asked Gough, did writers all “cluster under the same tree when there was a forest to explore”? Richard nods in agreement. “And comedy is also true to the life that we see around us. I’ve always thought that nothing I write is as funny as what goes on around me, not as funny as most people are at the end of a good evening when they’re surrounded by friends and slightly drunk. Laughter is such a big part of the way we live.”

But wasn’t he aware that many people found his enthusiasm for comedy peculiarly inappropriate when it was juxtaposed with pictures of starving children? Comic Relief might have raised nearly £500 million pounds for disadvantaged children in Africa and the UK since he co-founded it back in 1993, but it had also amassed a legion of critics who felt that putting on silly noses and acting daft every couple of years was a vulgar self-serving way of promoting a good cause.

“Yes, there is a slightly peculiar contradiction in my life between the Comic Relief side and the comedy writing side. But I can explain that. What we do on Red Nose Day is make things as funny as we can so that people can see the other side to all the sadness we show. I suppose what we are fighting for is that everyone should have the privilege of leading a happy life and being able to laugh like the rest of us instead of being worried that their husband is going to beat them up or they are going to die of a mosquito bite.”

Didn’t this argument play into the hands of those who described his charity work as sentimental, as playing with emotions rather than wrestling with difficult problems of policy and practice?

“I think ‘sentimental’ is a complicated word. A lost word. What is wrong with being touched by what goes on around you? I am very touched by what is good and true. It’s a family characteristic. It was very true of my dad in his final years. Whenever he talked of an act of kindness I can remember the tears in his eyes. And I can’t help being emotional when I come across something kind, when I find how warm people can be. But what struck me when I went to Ethiopia after the Live Aid concert was the lack of sentiment. I thought the nurses and the water engineers there would be highly charged, highly emotional, with tears in their eyes. But they weren’t. They were bluff northerners with beards busy drawing maps. They were doing something they did well for other people. And when I came home I decided to use my own skills in the same way. To see what I could achieve.”

When you’re sitting a few feet away from Richard Curtis it’s not difficult to succumb to his apparent integrity, his slightly defensive but utterly consistent claim that he can act in no other way because this is genuinely how he sees the world. There was a time at university when he used to argue with friends about politics but even then he was led to say to such friends that they might do more for the world by going outside and handing a fiver to the first homeless person they met rather than spending the next fifteen years working for the structural adjustment of society.

And it is, perhaps, this simple insistence upon charity as a good in its own right that seems to rankle so much with his left-wing critics and with many humanists and rationalists. Although they are predictably critical of Richard’s political naiveté and his failure to consider how charitable aid might be more a way of assuaging our guilty consciences than a realistic way of solving world poverty, I can’t resist the uneasy feeling that what many are really objecting to is the very act of charity, the practice of giving unthinkingly merely because one has been asked. I’ve even allowed myself the unworthy thought that perhaps this attitude has something to do with the notion that mere unquestioning uncritical charity is a particularly religious virtue, and one therefore that must be resisted along with a belief in heaven and the afterlife.

The association is very strong. Every single religion appears to place charity at the top of its list of religious duties. The Koran insists that “every person must perform a charity every day the sun comes up” while Luke demands that you “give to him who begs from you, and do not refuse him who would borrow from you.” Jews are enjoined by Psalms to “give justice to the weak and the orphan, maintain the right of the lowly and destitute, and rescue the week and the needy,” and the Buddha poetically asserts, “If beings knew, as I know, the results of giving and sharing they would not eat without having given, nor would the stain of selfishness overcome their minds.” What is often so central to these religious commandments, and so well captured in the figure of the Good Samaritan, is that once we have knowledge of someone else’s suffering then it is incumbent upon us to do something. Giving, as Curtis stresses over and over again in his campaigns, is just that. It is doing something.

But was there any hard evidence to confirm the link between non-giving and non-believing? By far the most extensive study in this area was carried out last year in the United States by Arthur C. Brooks, the well-respected professor of public administration at Syracuse University’s Maxwell School of Citizenship and Public Affairs. His nationwide survey led him to conclude, against his own expectations, that there “was simply no comparison between the charitable giving habits of those who attend religious services and those who don’t.” More than 90 per cent of religious people give money every year compared to 66 per cent of those who describe themselves as secular. And when they give, religious people give four times more than their non-religious counterparts. They are also considerably more likely to volunteer their time, give blood and engage in other acts of generosity and compassion. Nor is this simply a case of the religious dropping money into the collection box during church services. Religious people also give and volunteer more significantly to explicitly non-religious causes and charities.

Which religion a person subscribes to makes little difference. “I have never discovered any way in all of my research in which secular people give more than religious people,” Brooks concluded. And religion trumps all other explanations for charitable giving. It is considerably more significant than geography, race, politics or education.

There has not, to my knowledge, been any survey conducted in the UK that can match the comprehensiveness of Brooks’ work in the States. But small-scale studies tend to confirm his findings. Back in 2001, for example, a Social Market Foundation survey of giving firmly concluded that “believers on middle incomes give a significantly higher share of their income than those who did not call themselves religious.”

All of which makes Richard Curtis quite an exceptional person: someone who has devoted, and continues to devote, almost half his working life to charity and yet is a thoroughgoing humanist. There is nothing at all religious behind his charitable work.

“I stopped believing before university. This is going to sound facile. But I thought if God is worth worshipping then he must be at least as intelligent and knowledgeable as my own dad. And yet dad would always forgive me for the mistakes I made. There is no way in which he would look at all the pressures and temptations on a person and then still say that he should be punished. So I thought, well, either God doesn’t exist or he is thoroughly nasty, in which case I am not interested in worshipping him.”

So what was it in his background that inspired him to spend so much time and energy on relieving poverty and disadvantage? What lay behind his years of work on Comic Relief, his sponsorship with Bono of the massive Live 8 concerts in 2005, the Make Poverty History campaign and most recently the successful launch of Comic Relief in the States?

“Well, I have some very trivial thoughts about that. Perhaps it was something to do with spending three years of my youth in Manila where every day as my driver took me back to my house with a swimming pool I could see huge slums with people living under corrugated iron roofs. Then I suppose there was something in my upbringing. My mum cancelled Christmas in 1968. No presents. No special food. We gave all the money to the Biafra appeal. I was thrilled because it meant I could watch Top of the Pops which was normally spoiled by Christmas lunch lasting forever.”

It seemed a thin explanation. But then perhaps it was my fault for pressing the point, for trying to make Curtis exceptional. All the research that has been done into why certain people are more likely to be altruistic than others has come up empty-handed. It seems there is no such thing as an altruistic personality. When “altruists” are questioned about why they behave in this way, they simply respond by wondering why others fail to act in the way they do. It seems there is a banality about goodness as there is about evil.

But Richard is not in quite the same position as others who devote some of their time to good works. He is faced by a growing band of critics who not only doubt the value of his project but more woundingly suggest that his work is an exercise in image-building, both for himself and for all the celebrities who lend their names to his campaigns, who make up the crowd described by one commentator as “Saint Richard Curtis and his millionaire disciples”.

“I don’t think there are so many cynics. If you expected anyone to be cynical then it would be the comic community. But they understand it. I’ve only met a few people over the years who said ‘no’ to me and that was because they tended to be hardcore socialists who believe that you have get the state to pay for change. And I respect them for their opinion.”

Wasn’t this a bit naïve? My own friends hardly constitute a representative sample but their general cynicism about Curtis and his activities finds plenty of support amongst journalists and academics. Was he simply turning a blind eye to this section of society?

“Well, being the sort of person I am means I don’t have a very cynical set of friends. I believe that cynical people believe that everyone else is cynical. They regard non-cynical people as simply ultra-cynical. Supposed non-cynical people are merely pretending to be non-cynical in order to make money from other cynical people. So cynics who watch Love Actually think it is a cynical attempt to make money. No amount of evidence could prove to them that it ever had anything to do with good will. All I would do is encourage people with a cynical frame of mind to get on with it. Cynics Nose Day hasn’t raised any money yet.”

This seems the moment to tell Richard that he has a powerful intellectual ally. There is probably no better work on the psychology of giving and non-giving than the award-winning book States of Denial, written by my one-time co-author, Stan Cohen. Cohen is primarily concerned with analysing the various psychological techniques that allow us to disattend the evidence of suffering and hardship that lies all around us: repression, rationalisations, downright excuses. In one section he concentrates specifically upon the range of critical arguments that have been advanced against the methods of fund-raising promoted by Curtis and his associates, arguments which reinforce a determination not to donate to such well-publicised, celebrity-packed events as Live Aid and Comic Relief.

At the heart of these is the contention that Curtis and Geldof and Bono and others have promoted what one critic calls “Consumer Aid”, compassion through consumption. People are simply being encouraged to buy the paraphernalia that show that they care and then to watch pictures of themselves, or millions like them, caring. In Cohen’s characterisation of this position: “This allowed hedonism with self-delusion, while global television let them witness, and hence ‘consume’, the suffering and dying of the poor – and weave a message of self-congratulation about their generosity. Post modern altruism: the reality of famine turned into a spectacle, image-driven and self-referential.”

This, Cohen concedes, might sound like a new way of talking, but within it he detects some of the old familiar objections to charitable giving: the insistence that handouts encourage dependency and “exonerate donors from causal responsibility”; the view that the images used in the campaigns are racist and Eurocentric, designed to evoke only tear-jerking compassion, and not provide the true context of the misery.

Of course, Cohen says, such objections do matter “if the starving child and the corpses flowing down the river come to represent ‘Africa’. But surely these images cannot be suppressed. Needless misery, sickness and violence, millions of human beings losing their lives … this is the problem, the whole problem and nothing but the problem.” We might indeed be able to accompany the images with textual explanations, show that a typical African child is fed by its own parents, not by Joan Collins in front of a team of UNICEF photographers. But these are not merely “newsworthy events”. “They are the most deserving cases that need urgent help,” Cohen told me. “If Curtis and others had to think each time ‘about representativeness rather than representation, this would undermine – not to say miss the point of – their work.” He concludes: “I believe that unless ‘negative imagery’ is allowed to speak for itself, the universality of suffering will never be acknowledged.”

Would that, I wonder, help Richard in some of the arguments that he had to face from critics?

“I don’t argue. I remember learning – I won’t tell you when – but I had once had a very difficult working relationship with someone and I used to walk around the streets and try to win the argument. And I could never win. I could never imagine a scenario in which they agreed that I had been in the right. And that was a very important moment. It is hard to win arguments with people who disagree with you. The best thing to do is move on. I am, of course, interested in what you might call the clash between charity and politics. I think now that it is the job of the people who do charity to encourage politicians to take that work away from them. And I am increasingly convinced that what Comic Relief has done has been useful politically with the smallest ‘p’. Matters which were very contentious and charitable when we started in the ‘80s are now government policy.”

Did this mean that he would be concentrating even more in the future on working for political solutions?

“I am still not willing to wait. I would still prefer to go out and give a fiver to a homeless person than wait for society to change.”