My girlfriend says I frighten her. When she told me this, about six months ago, I was horrified. We seldom argue and when we do I'm never threatening. I've never been violent in my life. But, she said, when I'm in a mood, she's often terrified. What seems like a mere sulk to me is to her a rage so powerful it becomes almost a living thing. It swamps the flat, pushes the air from the rooms and bends out the walls.

I was so confused when she made this claim that I simply discounted it. It just made no sense. It was as if someone had said to me, 'So how does it feel to be made entirely of onions?' Nonsense! So I forgot about it. Until - for some reason - now. I'm about five minutes into a three-day intensive anger-management course, which I'm attending for purely journalistic reasons, to see if schemes such as these have substance or are merely get-out-of-jail cards for toxic celebrities, road-ragers and parole-hungry psychotics.

And I've been worrying about this story because, well, how am I supposed to judge the worth of this thing if I'm not an angry person myself? Rage really isn't a problem for me. Not at all. I look down at my pad, where I notice I've been absentmindedly doodling a beautiful fairy with a machete sticking out of her eyeball.

Tch! That's not right. I turn to a fresh sheet and copy the words on the flipchart in front of me. 'It's a beautiful morning,' our teacher, Mike Fisher, is saying, 'And I am in a joyful place.' I snort inwardly, then begin to transcribe the information carefully. 'Life is not a rehearsal,' I write. Then, 'Listen with LOVE.'

'The skills I'm going to be teaching you over the next three days,' says Fisher, 'are bloody powerful.' The door opens, an old woman pops her head through and says, 'Oooh, I am sorry!' before closing it. I sigh theatrically.

'I've heard stories of gang leaders in prisons being taught anger-management and using the techniques to manipulate people,' says Fisher. 'As a therapist, even I could use them for bad. What do you get if you write the word "therapist" down?' Mike approaches the flipchart and writes 'The Rapist'. I make eye contact with Oliver, the violent beautician to my left, and smirk dismissively. 'That's the danger,' says Fisher. 'That I will use my power to rape. Not physically, but psychically. I might go home and rape my wife, I might rape my kids...'

My right foot starts tapping up and down.

'And the concept of danger,' Fisher continues, 'is absolutely key here. Put a D on anger and what do you get? Danger,' he says. The door opens again. It's a different old lady. 'Oooh, I am sorry,' she says. 'Oh, for fuck's sake,' I mutter, shaking my head, my right foot now blurry with violent motion.

Old ladies. Annoying. Silly Californian therapising nonsense. Annoying. Chirpy gurus with goatee beards, acronyms, flip-charts, worthiness, three days in an airless peach-walled room with a gang of problem-ragers who probably all hate me. I want to ram my Biro up my nose just to relieve the blinding aggravation of it. But I won't. I'll just sit here, inside my sparking thunderhead of fury, and seethe.

I won't lose it with it anyone, though. As I said, I am completely in control; a zen master of the mind. I'm nothing like the four-stripe crazies who inspired this piece. Omar Sharif, for instance, who was ordered to attend anger-management classes in February after hitting a parking attendant who wouldn't hunt down his lost car for €20; Naomi Campbell, who also had to have a go after assaulting her maid with a mobile phone when she couldn't find the trousers she'd wanted to wear on Oprah; and post-downfall reality TV star Jade Goody who caused uproar with her voluble rage during therapy at the Priory.

But you don't have to be a defective celebrity to have a problem. Out there, on the streets of Britain, the anger's palpable. I'm surprised it's not affecting the weather somehow. Just consider the figures: 64 per cent of us suffer from 'office rage'; more than 80 per cent of drivers have been involved in road-rage incidents; UK airlines have reported a 59 per cent increase in air-rage incidents; one in 20 of us have argued with our neighbours; 50 per cent of us react to computer-related problems by screaming, shouting or punching our PCs. Further evidence comes from the simple fact that anger management has become a huge industry on both sides of the Atlantic, with Fisher himself writing a book on the subject. He is frequently referred to as Britain's top 'anger-management guru' by magazines, newspapers and television programmes.

'I'm sure people are getting angrier,' psychologist Oliver James told me when I called him up before the course. James is the author of Affluenza - the term he's conjured to describe the problem of the middle classes putting too high a value on money, possessions, physical and social appearances and fame. 'The affluenza virus creates a state of mind in which you don't meet your profound psychological needs,' he says. 'You're charging around like a headless chicken trying to pay off the mortgage or a better car, always wanting what you haven't got. You're feeling fundamentally frustrated because you're not getting your needs met and that frustration is the cause of anger.'

I asked Richard Layard, too, as he's one of the county's most respected economists and the author of Happiness: Lessons from a New Science. Although he says happiness trends are static, he points out that the things that make people feel pleasant are mainly to do with human relationships: 'Family, colleagues, community,' he says, 'and things have not been improving there. We are basically social animals and most of our enjoyment of life comes from contact with other people. I think if there was one thing that would define whether a person is happy or not, it would be, "Do you feel other people are on your side or do you perceive them as a threat?" Things have got worse there. In the Sixties, 60 per cent of people said yes to the question, "Do you think most other people can be trusted?" That's now down to 35 per cent.'

So, as my turn to 'check in' and explain my 'problem' to the group comes closer, I start to worry about it even more. What am I going to say? Well, the truth, I suppose. Which is that I'm no different from anyone else. In fact, if anything, I'm better than many, because I rarely lash out.

I hear what Layard and James are saying - we are all desperate for social significance and our trust levels are wearing concrete boots. I believe it. But, speaking personally, my 'problem' doesn't come from within. It's not my fault - it's not my value systems or status anxiety or fractured familial relationships that's the cause of all this. For me, it's something much more fundamental: it's the economy, stupid.

So I tell them a wonky theory, a furious hypothesis that coagulates in my head seconds before it spills out of my mouth. At some point in the past decade or so, I say, we've tipped over a brink, stumbled into some looking-glass, though which the economy doesn't serve us any more and we've become the slaves - we're now bullied, constantly, by businesses. They treat us with contempt when we clock in at work and after we've clocked out, too, in the heartless wastes of the free market.

This is why we've become so angry, why our fury is so bulging and unspoken. Because there's no one to blame but us. What are these corporations but teams of decent individuals just trying to excel at their jobs, because they want security, hope and happiness for their families? We are at war with ourselves.

So who do we take it out on? Who do we shout at? We're not allowed to 'do' anger at work, at the station, in the restaurant, down the phone to the call-centre operative (it's not their fault) and heaven forbid you rage at your partner or children. For the inhabitants of this shabby, fractious island, there's nowhere for the fury to go. So we carry it around with us, dangerously, everywhere we go.

I can feel my rage. It collects in the centre of my throat. It's like I've swallowed a cannonball and it makes me want to scream. I am brimful of anger, and when it sloshes out, it does so in the only direction it's allowed to - at inanimate objects. I shout at keys I can't find, at carrots I drop on the kitchen floor, at doors I stub my toe on. Last week I called a spilled glass of elderflower cordial a cunt.

This is all roughly what comes out of my mouth, almost unbidden, during my check-in. I don't really know where it came from. It was like going to pop a zit and unexpectedly having a 40lb tumour flop out. And by the time I'm finished, I'm damming back the tears. The feeling, when I'm instructed to examine it later, is one of abandonment. I am terrified, out there in the world. Utterly alone.

So, OK, I reason - maybe I am angry. But it's not my fault. And, therefore not my problem. The other attendees, however... Well, I'm honour-bound not to write about their experiences on the course. But I can tell you that they include a lady who recently drove to her husband's house with a kitchen knife and stabbed his tyres ('Nobody told me they'd explode'), another who has been informed by his fiancee that if he doesn't get 'help' she's calling off the wedding, and another who's an ex-football-hooligan turned HR manager on police bail after he caught his wife doing profoundly unwifely things - and the bruises that were left following the resulting argument were not solely of the emotional kind. These are people who have been hurled into the very troughs of despair by their explosive rage.

Fisher's course is part theory, part a process of unpacking his pupils; taking their rage to pieces and seeing what its motors look like. If there's one single goal of the intensive three-day course, it appears to revolve around teaching us how to understand and then accept ourselves in all our fallible glory. We need to learn how to decode the language of our emotions, to be wise about hunting down their causes and bold about stating them. If we know what we're feeling and why we're feeling it and are unafraid to tell the rest of the world, we'll suddenly find we're in command of ourselves. It takes away some of the terror of being human.

We spend the bulk of the first day on this unpacking process, chiefly in the form of these emotional 'check-ins', following which Fisher throws a series of questions and assertions in our direction that act like devastatingly effective sob-grenades.

Following my splurge, Fisher asks about my childhood. 'Not this again,' I think, as I begin to trot out all the things I've been telling strangers regularly for the past 12 years.

You see, since I left home at 18, I've sat many times in rooms like this one, decorated with abstract prints in cheap clip-frames, low-maintenance pot-plants and worn seats, rolling out these loveless stories as unfamiliar faces looked back, earnestly, pityingly. Counselling, psychotherapy, group therapy - I've ticked them off like a sightseeing tourist on one of those buses. I've shelled out fortunes sorting through all this messiness and filing it away. I don't need to do it again. It's over.

In short, the truth is this. Up until relatively recently, I've had a life spent hiding in bedrooms. During my childhood and teenage years I'd be up there, at the top of the house, as far away as I could get from the fury that awaited me downstairs. And in the years after I left home, you'd find me cowering under the covers still; shaking off the dreads of another alcohol, amphetamine or ecstasy comedown. I'd watch the walls change colour with the light of the day that was happening outside without me. I'd lie there, frantic with shame, my brain continuously presenting me with new and noteworthy illustrations of why I'm so appalling; why all the menacing prophecies of my parents had turned out true. The only piece of father-son advice my dad ever gave me was, 'Take it from me, the pursuit of happiness is utterly futile.' And, to give him credit, that's exactly how I've found life to be, from the day I learnt to walk until now.

But I'm less miserable than I used to be. I'm teetotal and have a stable home-life. I even have a genial relationship with my parents. Things are OK. And, you know, boo-bloody-hoo. Poor likkle middle-class William had an unhappy childhood. In the grand rainbow of human misery I barely register in the violet. I've done my decade of therapy, dealt with the doom, despatched the dependencies and I'm all right now.

So I know exactly where Fisher is going with this, and I'm bored of it. And it's got nothing to do with my anger, I'm sure. I'm older, now. Past all that. It's the mere act of living, here in Britain in 2007, that makes you mad. But, regardless, I indulge him. I tell my stories. When it's over, he asks, 'Have you ever tried to commit suicide?'

'No', I say, 'but most days I think if I get knocked under a bus, I wouldn't really mind. I don't think that's unusual.'

'Have you heard of slow suicide? Drink and drugs can kill you. Work can kill you.'

'I had to give up drink and drugs seven years ago.'

'Do you work a lot?'

'I'm working almost all of the time.'

'Don't you socialise?'

I pause. Fisher doesn't know it, but he's tapping on a fragile and bursting vein of insecurity here. When the pills and pints of gin and tonic left my life, the friends did, too. Sober, and without the discount superpowers that drugs provide, I find it nearly impossible to talk to people socially. The truth - the answer to his question - is stark and unavoidable. But I have to be honest. So I decide to just say it.

'I don't have any friends.'

There's a silence. 'You spend a lot of time trying to prove yourself to the world,' Fisher says to me.

'Well the world doesn't like me, people don't like me. The world feels like an unfriendly place,' I say.

Mike holds my stare. 'Listening to you makes me very sad.'

'Does it?'

'Virtually tearful. You've got a very fucked-up way of loving your father, my friend.'

I look down at my lap. Suddenly, I feel drenched in emotion. Mike glances at my sweatshirt. It says 'Coca-Cola' on it.

'You're living in a Coca-Cola world, right now. Does anyone know what I mean by that?'

'That he'll go pop?' says the knife-woman.

'Um, sort of,' says Mike. 'You need to live a more authentic life.'

'That's not true,' I say, defensively.

There's a noticeable twinkle in Fisher's tear-shot eyes and he says, 'Let's see how the weekend unfolds.'

Fisher used to be an 'extremely angry man' himself, he tells me over tea and vegetarian pasta bake that evening. A classic passive-aggressive 'imploder', he realised, years ago, that the source of his rage was his grandfather. 'He shamed me terribly as a child,' he says. 'He was very devious. He would mock me and describe me as stupid and useless and not good enough. It was very embarrassing, very shameful. And I picked up those messages and believed they were true.'

So Fisher, like me, spent years in therapy. But there's a twist. The 'talking cure' had a dangerous consequence for Mike. By the time he'd reached his early forties, he'd learnt that he didn't need to concern himself with other people's opinions of him, and that he was allowed to show his anger. And he went a bit crazy. 'I started to explode,' he tells me. 'My anger started spilling out in a very extreme form. I was very verbally aggressive. Very threatening. I sent out a lot of poisonous emails. I'd fly off the handle.'

'And when did you realise there was a problem?' I ask.

'When people started to disappear out of my life,' he says. 'When people started to stop taking me seriously, when people started spreading rumours about me. People were actually saying, you know, "You're unsafe."'

This realisation led to a period of study and training on the theories of anger that lead to his founding the British Association of Anger Management, eight years ago. Since then he was worked with more than 10,000 people.

And it's on day two that we begin to get the benefit of Fisher's hard-won wisdom. First, we learn that we become angry when our 'primary needs' are not met. We all have these, chirping away inside of us, like so many hungry chicks. We need to feel valued, safe, significant, successful, cared for, held and encouraged. We also have to have justice, trust, joy and so on. It's when someone gets in the way of one of these vital requirements that the fury comes.

Next, we learn about the Jungian concept of 'shadow selves'. Have you ever had the sensation of a stranger walking into a room and feeling suddenly gripped by absurd levels of hatred? This, says Fisher, is what happens when we encounter a person who is exhibiting one of our 'shadows', those qualities we possess but which we repress or deny in ourselves. Do you hate arrogant people? Greedy people? Or is your bete-noire the obnoxious, ungrateful or slutty? Well, welcome to yourself. You may have been taught, since before you can remember, that 'showy' people are bad. In response, you've spent your life deliberately avoiding designer labels or boasting about your holidays. Then in strolls Flash-boy Godwin, all bespoke cuff-links and diving safaris in Micronesia. And everyone aahs and coos. How comes he's allowed to do that and you're not?

We're also told there are two types of angry people - explosive and implosive. Which is something of a revelation. Implosive people rage on the inside. They tut, sneer, shake their heads and, you know, do stuff like doodling violent sketches on their notepads. So, just because I rarely shout, I learn, it doesn't follow I don't have a problem. I'm an imploder, Fisher tells me. And they can be just as scary. A sentiment my girlfriend, I realise, understands.

Fisher then asks me about yesterday's comment, about having no friends. I know the answer to this one - it's because I'm unhappy. And there's a pervasive myth about unhappy people. We're usually drawn as tragic figures, as the blameless victims of the baddies. But the truth is, we are the baddies. Our misery makes us rude, deceitful, bitchy, criminal. In the real world, we're just not nice. This is why I avoid people. It's less dangerous for me if I sit in my study drinking tea and guzzling St John's Wort. And it's less bothersome for others, too. I've learnt it's good to hide.

As day three begins, I'm not sure what to think. I've realised I am angry, albeit implosively. But it's a noxious combination of an unfair world and an unpleasant me that's to blame. And how does this evangelistic, red-trousered Michael Winner lookalike think he's going to solve that? By telling me to live a life that's 'authentic'?

'Anger is the symptom,' Mike says. 'And shame is the cause. Everyone here suffers from what I call "toxic shame". Shamers feel like they have been somehow cursed, that they're not like other people. They think, "I am flawed and defective as a human being", and, 'If you really knew me, you wouldn't like me."'

I don't make notes for this bit. I don't need to. Plus, I'm concentrating all my efforts on trying not to cry.

'We avoid facing our own shame,' Mike continues, 'by using such behaviours as...' he turns and writes on the board: perfectionism; control; resentment; criticism and blame; moralising; self-contempt and contempt for others; patronising; envy; indifference. 'Each of these behaviours focuses on another person and takes the heat off us. You need to practise what I call "radical authenticity". You need to accept that the authentic self is often not very nice. But by accepting your shadow-self you're accepting your humanity.

'We start out life being absolutely who we are and loving who we are,' he continues. 'But what happens is that people project all this shit on to us. And we start to learn we're either too much or too little; too big or too small; too clever or too stupid; and we learn very quickly that these behaviours are inappropriate. And then we learn how not to become ourselves.'

The final exercise is called the 'Detour Method'. When we find ourselves dramatically overreacting to an ordinary situation, this is, apparently, a sort of pain-response to a buried trauma. The theory is that if we can identify what's hurting when we spin into a sudden fury, then we can start to 'heal'.

As we break up into groups of two, I find myself becoming freshly dubious. We've been asked to relive a recent angry occasion, decide how old we 'feel' in our wounded state and then summon up an incident that happened to us at that age. This, apparently, will reveal the sore that's still weeping, causing us to go defensively mental when its touched.

'But aren't we trusting that the subconscious is going to present us with a relevant memory?' I ask Mike. 'How do we know it's not just chucking up a random negative recollection simply because I'm requesting it to?'

Mike smiles dreamily. 'You've got to trust the process,' he says.

So I try. I remember the last time I became angry. It was three days ago. My girlfriend and I are remortgaging our flat and it involves a lot of tedious form-filling. Ordinarily, all matters of import are left to me to deal with. On this occasion, though, I asked her to complete the application. Just for a change. First she didn't bother. Then, after three nags, she just filled in the bits she could do from her head. When I'd completed the rest of it and posted it, she got a call from a property valuation company to organise a visit. Her response? She gave them my name and mobile number. 'It made me feel totally unsupported,' I say. 'Totally alone.'

'How old do you feel?' asks my partner, following the precise Detour Method script.

'Um, 14?' I say, making it up as I go along.

'What happened when you were 14?'

I think for a moment. A still from an incident I haven't considered for years flashes up. It's a nothing, really. I don't even know why I still remember it. 'We were in the car, on holiday, looking for a bike rental shop,' I say. 'My dad was angry because we couldn't find it. He was saying, "Somebody help me." I saw a road we hadn't been up, a narrow one on a steep hill. He tried it and scratched the paintwork on the door. Then he started shouting - saying it was my fault. My mum told me to apologise, which I did. Then, later that day, she called me downstairs, from where I'd been hiding in my room. I thought she was going to say sorry to me, because it obviously wasn't my mistake. But she scolded me some more and made me go out to Dad and apologise again. I just felt totally unsupported. Totally alone.'

In that moment, I see the link. And, undeniably, it's powerful. That feeling of having no one on my side. It's exactly what it was like when my girlfriend let me down. Over the past three days I feel as if I've been on a reverse journey to the inside of myself. I've gone from bitterly blaming the world for making me unhappy, via my current relationship, back to a half-forgotten memory from 18 years ago. Three outwardly unrelated experiences, all of which appear to be connected by the same fear. Abandonment.

In the six weeks following the course the furious homunculus who's been driving my brain is noticeably more serene. Before, I'd spend my hour-long cycle ride to work gnawing obsessively at some problem or other, having fantasy arguments in my head, rehearsing defences that most of the time I'd end up not needing. Now, I recognise this is just anger 'coming out sideways'. So I take the time to fathom out what's really making me angry, isolate the fear beneath it, then allow myself to be authentically scared for a while, to 'sit in the discomfort of my hurt' as Fisher would have it. And - to my astonishment - it seems to work.

The biggest test of all, though, came eight days ago, when I was informed my job was going to be made redundant. As I type this, I'm petrified. I feel about 2ft tall, like I want to run off and live under a hedge, away from everything. But things at home have clung on admirably. Previously, I would have withdrawn so far into myself I'd have virtually lost the power to speak or move my facial muscles. The sulk inside our small flat would have been gigantic. But I've tried to talk to my partner about how I've been feeling and - bar an 'explosive' incident last night when I stormed out of the flat, took a random bus to Peckham and found myself sitting on a wall in a car park - we're getting through this well. And, best of all, my girlfriend tells me she's not been scared at all.

· For more information about the British Association of Anger Management, go to angermanage.co.uk