As far as I was concerned, anything to do with games at school was the big dread. In the 1950s there were hearty games periods every single afternoon, unless the pitches were three feet deep in snow, and this prospect induced in me, from late morning onwards, a daily dose of sickening funk.

Running about – hockey and tennis – left me purple in the face with misted-up (NHS) specs and exasperated teammates. Faced with the gym or the athletics field, my body (5ft 9in by the age of 12) behaved like a broken umbrella stuck in a tree, all angles, stiffness and panic.

I was full of awe and envy for the supple little ponytailed girls who spun and sprang so effortlessly and landed neatly on their feet, like nonchalant cats. Ineptitude and fear decided me, by my early teens, Against Games For Ever.

And so it was, for almost half a century. Occasionally, some intrepid soul would attempt conversion – my first husband, for instance, tried to teach me golf – or I would feel that I really ought to join the rest of the sensible human race and at least show willing, hence alarming skiing lessons (fortified by cognac for breakfast) or hopeless tennis ones (fortified by my extremely funny late friend Fiona).

No doubt because I was so talent-less, and certain of it, I declined to watch sport as well, avoiding jolly conviviality round the boat race or the cup final, and studiously looking the other way during Wimbledon fortnight.

And then – well, then I got older. One of the truly liberating joys of growing older is that some aspects of life that used to cripple one with some form of distress just mellow peacefully into simply not mattering. I discovered that running about badly and humiliatingly at 12 had somehow segued into running about (in much the same way) rather well at 62 as I played in goal for my football-mad, eager-to-score five-year-old grandson.

Wishing to play with – and please – Alexander led quietly, to my surprise, to an interest in what held this bright and original little boy so in thrall that his bedroom walls were completely covered with pictures of footballers, mostly from Liverpool FC, torn out of Match! magazine and stuck up enthusiastically and haphazardly with Blu-Tack.

Looking round, I also noticed that a great many of my cleverer friends were not only seriously interested in football but had been so all their lives, and that this was no cult affectation since these were people much keener on displaying intellectual and creative prowess than anything remotely social or even athletic.

I started to look at the sports pages of newspapers, and I realised that much of the writing was not just extremely good but also – right up my street – psychological. And I began to think that if I was going to lay claim to writing fiction that really reflected contemporary life, I was going to have, to some degree anyway, to include football.

I have always researched my novels – a habit, I suppose, left over from writing historical fiction. For the current book, Friday Nights, which is primarily about modern female friendship, I spent a wet Sunday two years ago walking the streets of Fulham, in west London, looking for the right houses and settings for my characters; and on my way westwards, I passed Stamford Bridge, the home of Chelsea FC.

I must have passed it hundreds of times in my life, without really taking it in. That day, however, I stood on the immense forecourt, under my umbrella, and gazed at it, and it came to me that one of my male characters, in his pursuit of one of the single mothers in the book, might well seek to ingratiate himself with her by taking her eight-year-old son to a football game. And if he was going to do that, then I had to do it too.

Lady Luck was on duty. Bradley Rose, driver supreme for my paper-back publisher, Transworld, has been going to Stamford Bridge since he was seven. He was sent, in the care of his older brother, to stand at the Shed end, since their father considered the family’s local ground, Highbury, where Arsenal used to play, too dangerously violent then for a small boy.

I applied to Brad. Would he take me, just the once, for the sake of fictional accuracy? I envisaged an interesting afternoon with my notebook, which would neatly provide me with the authentic details I needed for chapter eight, all done and dusted in a few hours.

Brad was admirable. He agreed, gave me just enough guidance to make sure I behaved properly in a football situation and then left me to it. I had been given a seat normally occupied by his brother David – thank you, David – in the Mat-thew Harding stand, and was going to be surrounded by a gang of the Rose brothers’ football mates. “You might”, Brad said calmly, “find the language a bit fresh.” He bought me a chicken pie and a lime and soda and led me up a series of sternly stewarded staircases and passages, on and on, higher and higher and out – into the stadium.

I could not believe it. Even now, writing about it, I can feel that first surge of excitement and amazement at the size of the thing, the space, the greenness, the number of people. Apart from some concerts at Wem-bley, I’ve never been with so many organised people, 42,000 of them, already braying and bellowing away in all those crude, seductive chants that give you, in these complicated cultural days, such a glorious, simple feeling of belonging.

The game itself was eye-opening. Seeing a whole pitch (not just televi-sion camera slices), witnessing the speed and deftness of the players, the atmosphere – all of that has been described so often and so well by so many that all I need to say is that I was bowled over. I couldn’t believe how gripped I was, nor how dismayed I was when it was over, even though we (yes, I was an instant convert to Chelsea) won (2-1 against Portsmouth).

I went home on the kind of high remembered from really good exam results, and lay in bed reading the programme, detail by detail. I thought of Alexander’s bedroom walls with absolute empathy.

It isn’t fashionable, I know, to champion Chelsea. The chic teams to support are Arsenal and Liverpool, or else, slightly defiantly, somewhere like Leices-ter or Southampton. But Chelsea is where it began for me, and football loyalty, I have discovered, is a visceral, not a rational, matter, and is only strengthened by unpopularity or periodic failure. So Chelsea it is for me. Period. And to prove it, I have applied for a season ticket.

In any case, Chelsea have been extremely good to me, putting me on their website and in their fan magazine and – an invitation that has aroused exactly the awe and envy in my friends that I used to feel in that long-ago school gym – asked me down to Cobham to see their training facilities and meet some of the players.

I know. I will pause here to acknowledge that I was very privileged, and that for someone whose research is inevitably and frequently rather sobering it was a marvellously fresh and invigorating thing to do.

Roman Abramovich, whatever he is or isn’t, has built his team a palace at Cobham. And before you sneer, it’s my opinion that every serious team should have such a palace. I arrived early on a December morning – the players have to be in for breakfast by 10am – and was shown over the whole gleaming building, with its pools and gyms and therapy suites, its press offices and meeting rooms, its enormous, beautiful canteen, complete with pool table, overlooking the huge green spaces of the training pitches, backed by the tidy houses of residential Cobham.

Of course it’s glamorous. Of course it’s luxurious and splendidly equipped. But as I walked round it, with only the administrative and press staff yet at work, the overriding sense was of an immense and professional business, a well-oiled and well-functioning machine with a vital but unpredictable human element at its heart – not unlike the feeling you get backstage at the Royal Opera House, where dancers and singers provide precisely the same crucial cocktail of magic, caprice and fragility that these physically talented young men give to football. And I’m sure that it’s the tension between the two – the business and the performers – that gives the place, and the game, its unique and beguiling energy.

At about 9.30, the players began to amble in, dressed in Chelsea training strip, garnished with scarves and beanies. Several of them were smaller than I was expecting, and slighter, and some of them were accompanied by their little boys – it was the Christmas holidays – who skirmished happily about from man to man, completely and endearingly unaware that there was anything remotely unusual in having a world-class footballer for a father.

I noticed that as each player came in – John Terry still on crutches, Frank Lampard bigger than I’d expected – they went round the room high-fiveing or thumping one another on the shoulder by way of greeting, and in most cases they came over to shake my hand as well. Gosh, I said, I’m impressed. Well, they said, it’s Didier (Drogba, otherwise known as Chelsea’s goal machine), really, brought up in France the formal way, with bon-jours and bonsoirs all round at the beginning and end of every day, and he kind of started it when he came three years ago, and now it’s a habit; we all do it. And very pretty to see it is too.

So was watching them have breakfast. I expected them to have manly platefuls of eggs and bacon, but mostly they ate what their little sons ate: rice pops with milk, and Mar-mite toast fingers, with English going on at one table and the French of francophone Africa at another, and Avram Grant (the Chelsea manager) wandering round the edges, eyeing his boys but not talking to them, not interrupting.

The atmosphere was friendly and easy and undramatic. Drogba obligingly signed a poster of himself for my Alexander, and for his older sister Maria, who shares my feelings for Chelsea, and Frank Lampard, refilling his tea mug, asked if he was really in my novel.

“Certainly you are.” “Mentioned by name?” “And your father. I describe a photo of you both – you standing behind your father with your arms round his shoulders.”

Lampard (Maria’s hero) gave me a wide, white smile.

“Wow,” he said. Then out we all went, into the bright, bitter morning, onto the training pitches. And there all the sleekness, the stardom, the evidence of limitless oil money vanished from the picture. I stood in the wind beside a smallish square of muddy turf, inside which Henk ten Cate (the assistant manager and coach) – not an approachable-looking man – had half a dozen players passing the ball in short, sharp movements, over and over and over again, constantly changing angles, yelling, contradicting, yelling again. I was there for 20 minutes and none of them stopped moving – fast – or glanced up for a single second. Only practice makes perfect.

Now that the book is out (with a boy in a Chelsea shirt included on the jacket) I’ve had plenty of time to realise that this enthusiasm for football is here to stay, and to consider what it is about football that has had such an effect on me.

I suppose that the first reason is that I am at last free to appreciate sport because nobody expects me to participate in it – except small and forgiving grandchildren – and so I can, for the first time in my life, sink into enjoying it. I can be deeply interested in it from my mental and physical armchair; there is nothing, praise be, to be proved athletically any more. As with most things, I can probably achieve much more with my head than with the rest of me – for example, I now find I read the football press almost every day, and miss it during the summer holiday.

The second reason goes back to that first dose of football chanting two years ago. We live – often for excellent reasons – in a world of insisted-upon tolerance and verbal restraint, and although this is commendable in many (if slightly priggish) ways, it is a wonderful relief to have an area of life where it is permissible, even encouraged, to be intensely, unashamedly partisan.

A third reason is the human connection. There is no other arena that I can think of where you can, so naturally and safely and unaffectedly, be with such a vast body of other people, of every class and caste, of every age and type, all united by enthusiasm for something that, although it is immensely subtle and skilful, offers no opportunity for the intellectual snobbery that can afflict, say, music or the theatre. And it’s not sexist, either. I’ve noticed a lot of women, of all ages, at games, looking both involved and perfectly at home.

And then there is the game itself, played by beautifully athletic, supremely fit young men – you’d have to be the most chronic of old misanthropes not to rejoice in that. Yet – and this just adds to the depth of football’s allure – even the fittest and the best can’t play for ever. Football is for young men, and thus there is a poignancy and an intensity in watching them play in their physical prime.

I wouldn’t have felt all this, younger. Nor, before the horror of Hillsborough, would I have had the opportunity – a football stadium was no place to take your child or your girlfriend or your granny.

There is often a – regrettable – tendency to think that the past offered life in a purer, less debased form; but in this instance, I couldn’t disagree more. Football and I just had to be ready for each other. It may have taken nearly 50 years – but it was worth the wait.

Friday Nights by Joanna Trollope is published by Bloomsbury, priced £18.99. Copies can be ordered for £17.09, including postage, from The Sunday Times BooksFirst on 0870 165 8585

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