Towards the end of 2009 I returned home to Norfolk after a boozy night in London and, feeling every one of my 40 years, I decided it was time for a Special Bath. I turned the taps on full, lit a few candles, put on some Harold Budd and Brian Eno ambient music and squirted a thick green jet of Badedas bath ‘gelee’ into the tub as it filled, churning the water with both hands to build up a green mountain range of pine-smelling bubbles.

A few minutes later, finally luxuriating in my Special Bath, I decided I might like to switch from Eno and Budd’s reverb-heavy piano minimalism to the Blade Runner soundtrack and I raised a hand through the bubbles to activate my smartphone. But once I’d wiped away the pine-fresh foam, I was shocked to see that my hand suddenly looked like an old man’s hand: not just wrinkled, but papery and marked here and there with little brown dots and splotches over big knotty veins. ‘Fuck,’ I thought. ‘I’m old.’

I started to imagine that I had lost consciousness as a 30-year-old and woken up to find myself aged 80, then wondered if that might be a good premise for a film. It struck me that it was a nice excuse to email Dad, then in his late eighties, and ask him for his observations about ageing.

My contact with Dad in those days was infrequent, and what messages we did exchange were usually short and to the point, but my email about old age must have caught him at the right moment, because the next morning there was a reply in my inbox entitled ‘Random Thoughts on Old Age’. It was filled with insights, observations and a few relevant aphorisms that he had collected over the years. He often talked of compiling these as an annotated book of quotes called Words of Wisdom, though that was another in a long line of money-making schemes that never quite came together – a bit like my film idea, which also got shelved in favour of less ambitious but more achievable projects.

I forgot about Dad’s email until after he was dead. It popped up again when I was in the process of looking through old bits and pieces in the course of writing this book, and it struck me that it was probably the longest single communication he’d ever sent me, and in an odd way the most heartfelt. I was a decade older than I was when I first read it, and observations that had originally struck me as typically pompous were suddenly as grimly relatable as Michael McIntyre routines. See what you think.

A very common phenomenon, even in middle age, I am sure, is the appalling moment when one realises that a large part of one’s life has suddenly vanished without trace, like a mountain climber suddenly disappearing into a bottomless crevasse. I vividly remember such a moment in my own life (I was probably in my late thirties or early forties) when I actually exclaimed out loud, ‘Where did it all go?’ This is why one must always be on one’s guard against that so tritely but so very aptly described danger of regarding one’s days as if they were a rehearsal for the real thing, instead of being one’s never-to-be-repeated LIFE ITSELF.

Yes, we should carpe the diem and take some time to watch C-beams glitter in the dark near the Tannhäuser Gate, because life moves pretty fast and if you don’t stop to look around once in a while, you might find you spent most of it watching and rewatching films (and of course bonus features).

‘You’re as young as you feel’ may be thunderingly trite, but it’s also profoundly true. Health is not the prime conditioning factor here. Ill health and old age present their own syndrome, but a man can be perfectly fit in body yet behave as if he were verging on the geriatric.

Disbelief is probably the old person’s most common condition of mind. He hears expressions such as ‘the elderly’, but only with difficulty associates himself with that company. Looking for cheap second-hand books, he explores a charity shop called Help the Aged, but does not for a moment see himself as an object of the requested benevolence. He has a bus pass, and values it, but is not entirely convinced of his entitlement to it (though it is obvious to him that the gent sitting across the way is a fully qualified holder of the same device).

This is why the admonition ‘Oh, for heaven’s sake, act your age!’ can be so offensive and such bad advice. The intelligent senior citizen eschews the expression ‘at my age’ to preface a statement not simply because it is exceedingly pompous and boring, but because he knows that to get into the habit of acknowledging his years (or claiming them to gain advantage) is a sure way of accelerating the ageing process.

This reminded me of Joe when he was about 16 telling me about getting told off when he was pissing about on the Tube one day. An older woman told him to ‘grow up’ and Cornballs proudly reported to me that his response was, ‘Why would I want to do that?’ I remember feeling that I might have been on the woman’s side.

One doesn’t ‘feel’ old ‘in oneself’ but is nevertheless all too often disagreeably reminded that the ever-youthful mind inhabits a mechanical contrivance that is not immune from mechanical wear and tear. It’s a wonderful autumn day and one sees oneself taking a picnic lunch on one’s back and walking the 17 miles from Lewes to Eastbourne over the Downs between early breakfast and 6 p.m., as one used frequently to do, then remembers that yesterday it required a considerable effort of will to complete a three-mile course (though much of it steeply uphill) in an hour and three-quarters.

Dad was always a keen ‘hiker’ and continued with his walks on the Sussex Downs until he moved in with us. Occasionally he’d bump into someone who would recognise him from his BaaadDad days and it always made him happy. There was one particular meeting Dad described to me by saying: ‘I was out walking the other day and I met a fellow on a mountain bike. He stopped and said [does weird cockney accent], “’Ere, I know you! You’re BaaadDad, in’t ya?” I said, “Yes! That’s right,” and we had a very nice chat. But how strange that one should be recognised all the way out there on the Sussex Downs, don’t you think?’ I said I didn’t think it was that strange. The Adam and Joe Show was a ratings juggernaut.

Years after Dad’s death I discovered, through a series of minor coincidences, the identity of the cockney mountain biker. It was the Turner Prize-winning artist Grayson Perry. According to Grayson, who it turns out used to watch The Adam and Joe Show, he had spotted my dad on the Downs twice and they chatted both times.

There are many ADVANTAGES to old age, provided that one has learnt one’s lessons. PATIENCE is one of the most precious of these, though one of the hardest to acquire.

‘He that can have patience can have what he will.’

BENJAMIN FRANKLIN

‘Never think that God’s delays are God’s denials. Hold on; hold fast; hold out. Patience is genius.’

GEORGES-LOUIS LECLERC, COMTE DE BUFFON

To these I would add:

‘Have another slice of chill cake.’

A. BUCKLES

FORTITUDE. It is quite comforting to know that one is capable of surviving the injuries inflicted by the slings and arrows of outrageous fortune without falling about, and that one is capable of doing so much more than may at first seem probable.

The key phrase here is ‘without falling about’. Though Dad would never have referred to anyone as a ‘snowflake’, disparagingly or otherwise, he was never comfortable with people sharing every hang-up and anxiety and felt that to do so was to ‘fall about’. If something was really wrong, a person should ask for help, but as for feeling scared, sad and hopeless now and then, well, what did you expect?

As Dad was so fond of reminding us, ‘Life’s a vale of tears,’ but if you keep plodding on it’ll generally brighten up.

I’m on board with some of that philosophy, but being able to talk about how you really feel now and then is useful, too. As long as the falling about is kept to an absolute minimum, of course.

INDIFFERENCE tends to come with old age. Not mindless indifference (which would preclude COMPASSION and consideration for others), but the NOT CARING about a whole host of things that used to concern one. (At the most trivial, for example: I used to be quite irritated by people I didn’t know addressing me by my first name. I still think it’s very bad form, but I don’t care any more. I don’t care where the knives and forks go or if a red glass is used for white burgundy; it doesn’t affect the TASTE of the wine.

On the other hand, I don’t care very much if people jump the queue as long as I’m not especially anxious to get back quickly from the supermarket or racing to the catch the train. And I don’t care what people in general think about my writing; only about the opinions of those whom I happen especially to respect. The list is long and everyone will have their own.

I look forward to achieving a similar state of relaxed indifference, especially after all the time I’ve wasted worrying about negative opinions from disgruntled and even perfectly well-gruntled strangers on social media. But there’ll be climate change in hell before someone uses a red glass for white burgundy without me fully losing my shit.

When I was reading back Dad’s email I had just spent several weeks not only sorting through boxes filled with his old letters and photographs, but rereading my old diaries and notebooks to check memories and chronologies for this book. It was a process that started out fun but left me feeling shredded, the way I wished some of my diaries and notebooks had been. Then, when I read Dad’s email, it was as if he was sat with me and sympathising – not something he had done since I was about seven and upset after some children teased me for being short and having small eyes.

Literally and metaphorically, one goes into the attic, looking for reminders, and is overwhelmed by the accumulation of things, most of which have been completely or in Freudian analysis probably PURPOSEFULLY forgotten. It is dangerous stuff and can result in severe emotional distress. The mistakes one made; the wrongs endured or inflicted on others; the hopes shattered; the irreplaceable losses suffered; the projects of high promise unfulfilled ......! It is a bit like turning over a compost heap where discarded material has not yet had time to achieve a useful metamorphosis.

Putting things to the back of (or out of) the mind is an indispensable aid to a salubrious existence and to disinter such things can be a noxious exercise. The odours of the past can be less than fragrant (the dead rat as well as the faded rose petals or the pressed gardenia).

The attic can be a Pandora’s box, among the most pernicious of all its contents being that of REGRET. Only a stout philosophy can save a man from this particular evil. Here are two aphorisms taken from Words of Wisdom: ‘Your past is always going to be the way it was. Stop trying to change it.’ And, ‘A prudent man will think what fate has conceded to him more important than what it has denied.’

At the same time, the old ought to remember that the last item in Pandora’s box was HOPE.