I would like to make a public apology. More than that, I would like to announce, for the record, that I truly intend to mend my ways. It seems I have, for some time (a couple of decades, at least), been regularly offending my family, my friends and my work colleagues at mealtimes. I am finally facing up to the fact that I have a problem: I am a habitual food thief - a serial stealer of tempting morsels from other people's plates. I now realise - and it has taken me a pitifully long time to draw this conclusion - that it is wrong, and it has to stop.

But I know it will be hard. The compulsion to snaffl e the last piece of crispy duck (for example) on my neighbour's plate is overpowering, even, or perhaps especially, when I know he or she has been saving it for the end (precisely because it is such a fine morsel). Sometimes I barely even know I have done it. Exchanges such as the following are not uncommon: 'I can't believe you just did that!' 'Did what?' 'Took that strawberry off my plate. The one with the small but perfectly sized blob of cream on it. The one I'd been saving to the end ...' 'I didn't!' 'You did. I just watched you. I was so shocked I couldn't say anything until it was too late ... ' 'I really don't think it was me. Are you sure you didn't just finish it off subconsciously, while you were listening to your other neighbour's fascinating story?' 'Look. You had the chocolate roulade, right?' 'Yes.' 'So how exactly do you explain that little red-streaked smear of cream on the end of your fork...'

I know that I am not a lone perpetrator of this crime. I suspect my fellow off enders are mostly, but not exclusively, men. We have a greater gift for self-delusion than women. And in this case the delusion is a mighty one. We kid ourselves that there is some playful charm, a forgivable, even lovable quality about our behaviour. We even seem to think these acts of petty gastronomic theft bestow and elicit aff ection on and from our victims, so that our plate-picking habit actually makes a positive contribution to the general bonhomie of a shared dining experience.

In fact, a common defence which I have been known to employ goes like this: 'It's not stealing, it's sharing. Er, try a bit of mine ... (To which the likely reply will be, 'why exactly would I want a withered lettuce leaf with a yellowy brown bit on the edge? You never even offered me a scrap of one of your scallops, and now they're all gone.')

These scenarios are most often acted out with a female fellow diner - not infrequently my wife, and sometimes even my mother (the shame!). For although this is not straightforwardly a battle of the sexes (I have stolen plenty of fine things from the plates of men and boys) it is certainly compounded by the general tendency of men to eat all the most tempting-looking things on their plates first, while women so often save the best until last.

Whoever my victims are, such behaviour rarely passes without comment. And I have hardly ever met anyone who didn't mind, at least a bit, having their plate picked. Given that such mealtime skirmishes have been going on as long as I can remember, on an almost daily basis, you may be wondering how it is possible that I have taken so long to achieve any insight into the severity of my problem, and the extent of the accumulated irritation and misery I have caused.

The reason is, I believe, that I and others like me, are aff orded the powerful protection of the tacit social rituals of eating. In each individual case, the damage is relatively small (I don't eat all the food on their plate - just the bit they wanted the most). And so they are constrained to keep the irritation expressed relatively mild. However annoyed they may be, nobody wants to make too much of a fuss over a little bit of food, lest it be thought it is them, and not me, who has a problem with their food, and is allowing it to spoil the party.

So, inevitably, it has taken a bit of a shock to bring me to my senses. As so often in life, to bring about change, one bold individual must speak out, and give voice to the thoughts that many have merely internalised for so long.

That individual is a cameraman with whom I have been working regularly for almost 10 years. I am very fond of him, despite the fact that he gives me a consistently hard time, in an imaginatively foulmouthed way, whenever we work together. We must have sat at the same table dozens, if not hundreds of time. Which means the amount of food I have had off his plate over the years could probably be measured in kilos. I've taken a barrage of abuse as a result - but never so much that I wasn't able to persuade myself, if I thought about it, that it was all good fun.

That all changed last week, during a very excellent dinner at the Star Inn at Harome, Yorkshire, near where we had been filming. He was enjoying his slow roast belly of pork, with a particularly provocative pile of fine crackling on the side. I went for what was probably the penultimate piece with my thumb and forefinger. For once he was too quick for me, and gave me a sharp jab with his fork. 'No!' he said. 'You are not fucking having it! And if you do that to me one more time, I swear I will pick up my fucking fork and stab your hand so fucking hard I will pin it to the fucking table! And I mean that!' The rest of the table, was reduced to awed silence. And I could tell they approved his sentiments.

The severity of this threat was eased somewhat by the twinkle in his eye, and the fact that we were well into our third pints. I do not believe he is truly a violent man, or that he would ever really have carried out his threat. In fact, it was not so much the colourful language, or the graphic, Goodfellas style punishment he was conjuring, that shook me up so much. It was a subtle nuance of his grammar: '... if you do that to me one more time ...'

Those words shattered the biggest delusion of all: that mine is a mischief perpetrated not on a person, but on a plate of food. And therefore, that no harm is really done, that this is a victimless crime.

I now know differently. I have discussed it with other recurrent targets of my greed - and they're all on his side. They have collectively encouraged me to confront my disorder. They have promised to act swiftly and ruthlessly if ever they see my fork or my fi nger hovering towards their plate. The suffering, they say, has gone on too long. Now it will be my turn to suffer - the twisted agony of self-denial. It will be hard, and it will be painful. But it will be no more than I deserve.

· To buy signed copies of Hugh Fearnley-Whittingstall's River Cottage Diary, at £12.98 with free UK p&p, call the Observer book service on 0870 836 0885 or go to Observer.co.uk/bookshop