When older male celebrities have children there seems to be a kind of ripple of triumphant approval. I’m as happy as the next person to welcome new life (on to our wildly over-populated planet) – hurray for Paul McCartney and David Jason at 61, Pavarotti, 68 and George Lucas doing it at 69 – but my heart goes out to those children. I hope they won’t have to face what I did.

My dad was 64 when I was born. When he was 75 he had a major operation for thyroid cancer.  This was the start of his decline, but we didn’t realise it then because his cancer was completely cured.  A few months later the police found him driving along the hard shoulder at two miles per hour.  Then my mum and I began to understand.  I was 11 years old.

Now there are an estimated 700,000 carers under the age of 18 in the UK. In 1980 I joined the ranks until my father’s death in 1991.

I remember the 1970s very clearly. I’m growing up, six, seven, eight and my parents feel slightly out of synch with other people’s. Mum is 33 years younger than my dad. At school, other children want to know why grandad always comes to collect me. On the rare occasions that my half-brother is around, people generally assume he is my father. There is a telly ad I love featuring a dad and son playing football together. I take the football hopefully to the park but it never happens. The few times he does agree to pass the ball back it feels like a damp squib – he isn’t nimble at 74.

The first effect of my dad’s stroke is that he ca, ca, ca, ca can’t get his words out. I wait for sentences that he never finishes. His hearing is also going. His hearing aid makes a squeaking noise so he regularly throws it across the room in fury. Dad can’t hear much of what is said and when he can, he can’t get a response out. He is beginning to be trapped in his own body. Either he isn’t aware or he is in denial, but that doesn’t stop dad going to work. Dad is a psychiatrist, so talking and listening are obviously essential. Patients are starting to leave. Mum can’t persuade him to stop. He is still prescribing and giving injections. Nervous of what might happen Mum begs his friends to have a word with him, but they are unwilling to take on the role of forcing him to retire. Finally, one agrees to have a meeting with dad. The meeting comes and goes. Dad carries on working.

Dad looks after a number of patients from the theatre and ballet worlds. He is given free tickets to a West End show by a performer he is treating. I drive up into town with dad, but he is beginning to slow up physically and his reactions are not up to driving. We roll back into a car behind. There is a smash on the window as the driver slams his hand against it in rage at what has just happened. Dad stares ahead, “Quatsch” (“rubbish” in German) is his dismissive reaction and just drives on. This sends the driver into the stratosphere, he manoeuvres his car in front, forcing Dad to stop and give his details. So we get to the theatre in the nick of time and are shown to the star’s dressing room.

I’m presented with signed merchandise from the show and the performer says why don’t I wait on a chair; Dad gets his syringe ready to give a vitamin injection. I can see Dad’s hand shaking and the performer can’t understand what’s he’s saying. Nor can I.

Dad is having a problem getting the needle to stay on the syringe. The patient yelps as Dad starts the injection in the wrong spot. He squints closer and closer to try to see the vein and with unsteady hands he tries several more times. We leave the patient to get on with the performance, but it’s really not OK. I sit through the show afterwards feeling crushed at what I have witnessed. I don’t want to see my Dad fail like that. On the way home we roll into another car in traffic, but that driver is much more relaxed.

Things have been getting worse for months. Money is short. The hospitals Dad visits have now all retired him. He goes to sit several days a week in a consulting room with a dwindling number of patients who complain they can’t understand him and are getting bruised injections. The patients start to turn up at the house. Now things start to feel really out of control. Mum consults me and I’m about 12 now, and we decide to listen behind the door to find out what’s going on. We can just see the patient writing out a prescription for some uppers and puts it in front of dad to sign. Dad seems to be in a muddle and isn’t able to say much. The patient is determined to get more pills. Dad acquiesces and signs the prescription. My mother bursts in and tells the patient to leave. Dad rages and I leave them to have another row.

Mum is now convinced he will injure or kill a patient so she consults me on how to stop him. She suggests hiding his trousers and shoes so he simply can’t leave the house and I remove the pin and handle from the Ingersoll lock on the front door, so he can’t get out. We get out of the way as he rages round the house in his shirt and underpants.

I am miserable because one of the two people I love most is not recovering from his illness. For months I wait and I just don’t get it. He’s not going to get better. Things are bleak and miserable. But, bizarrely, things aren’t all bad. I‘m more like an only child because my half brother hardly ever stays. Our house (Gran lives with us too) is full of old people. It’s kind of boring. I can’t say I wholly enjoy all the dramas, tears and anger, but it certainly breaks the inertia of the boredom that surrounded us before. What’s more, my position in the household is inverting. Mum now consults me on everything, including how to deal with Dad. I get attention from her in my new role as carer. I get to choose the rules. Mum is all mine. I have won. Who’s the daddy now?

At 12, I was angry with Dad for not getting better, frustrated by the speed, or lack, of recovery and beginning to grieve for the loss of the father I’d known. Dad, unable to get words out, would lash out at me or Mum. I was usually too quick and ducked out of the way, but sometimes he struck mum. On those occasions I was filled with loathing. He had been the gentlest, kindest most patient man you could imagine. But being trapped first in his body and then being barred from work and often unable to communicate proved unbearable.

So if the beginning of his care was at times dramatic and shocking – and it was then on to helping mum get up to speed on incontinence products – the second stage was agonisingly prolonged. The next seven years saw a gradual decline in continence, mobility and general health. My mother was on a crusade to keep him in our house and not put him into a home. He was a full-time responsibility. Occasionally he fell and there needed to be two of us to get him on the move again. He was a large man, so even getting him comfortable in his chair or bed meant lifting with two people. Every meal he was walked through to the table. First there was a stick, then a frame, then me or my mum moving his feet, one step at a time, then in and out of a wheelchair before finally being bedbound. There were pills to deal with, food to chop or liquidise and feed, incontinence pads to change, incontinence sheets to lay down and change, and eventually a catheter bag to empty, sores to wash and dress.

Dad, however, was very much alert and alive. Just trapped in his body. For those people who jump to the “better off dead” pronouncement, I’m not convinced. Yes, for 10 years he was unable to speak, often unable to hear, unable to write, but very alert. He often used to sit in silence just looking at me or mum, smiling, content to be with his family, at home and being looked after.

Young carers are often invisible out of family loyalty, stigma or bullying. At 13 or 14 I would certainly not have been able to discuss the sight of my dad wondering down the corridor urinating all over the carpet with anyone except Mum. No way would I have told anyone at school. School work certainly suffered after my father became ill. Previously I had been a hard worker, but I switched off in class. It all felt secondary to what was unfolding at home. I went off to university in Leeds but came back to Shropshire every weekend and during the holidays to help look after Dad. I remember waiting in the queue for the payphone at uni which was separated from the corridor by a few bits of hardboard. You could hear everything and I’d be chatting through details of Dad’s care. I hated that others could listen in on my family secret. For the last few years my half-brother was able to come and help out which was brilliant because it became easier for me to escape. It wasn’t always easy to break away. One weekend I didn’t go home from uni but arranged with mum that I would visit a friend at their college in Cambridge. During that weekend she left over 20 messages at the porter’s lodge of their college. Mortifying.

The final stage of Dad’s illness involved him contracting pneumonia three times a year. Mum prepared us for the worst. Then Dad would get better. When he did finally die it felt underwhelming. The dad I yearned for had already been dead for 10 years.

My mum cried every day for years after he died. When I was 28 she was diagnosed with pancreatic cancer and died 11 weeks later. There was an amazing GP in Shropshire who had also been my father’s doctor. I remember him asking me after her death: “What was it with your mum? Looking after your father like that? That sacrifice for all those years? I’ve never seen anything like it? Why do you think she put herself through that?”

It had never really occurred to me. I think she just loved him and she didn’t want their world to fall apart. The two people I have subsequently had a significant relationship with have both been young carers. We had to step up to the plate when family loyalty and duty were up for grabs. They get it. We’re different.

Dogfood Diary by Laura Bridgeman and Charles Lambert will be broadcast on Friday 19 December at 2.15pm on BBC Radio 4 and will be on BBC iPlayer until 18 January. ChazzaLambert@twitter