Being from a single-parent family is hereditary. In my case, I got it from my father, who left my mother before I was born. Like most hereditary conditions, from time to time, you’ll find yourself discussing it in circumstances you can’t control and in a manner that makes you mildly uncomfortable.

In my case, well-meaning people ask what my father does, which leaves me with the unlovely choice between honesty, which makes the questioner feel awkward, and lying, which is hard to keep up for long.

Honesty is particularly fraught, because an eccentric minority always believes that the polite response to “I don’t know, we’ve never met” is to ask, “Why not?” and inquire whether I ever wanted to meet him.

Quite why this is considered appropriate conversation at a social event has never been clear to me. My father left because he wasn’t, at that time, interested in having either a long-term relationship or a child. We haven’t spoken since because I haven’t wanted to make contact, and neither has he.

Before the era of Facebook, Twitter and LinkedIn, I might have wanted to meet him – to find out what he looked like, if nothing else. But thanks to Google Chrome’s “Incognito” mode, I have been able to ascertain the most important detail, which is that both sides of my family boast full heads of hair well into their fifties but that, sadly, what we retain in volume we do not match in colour.

I’ve learned to enjoy the upsides of having an absent father. One is that you don’t have flaws like everyone else, merely kinks that the missing parent would have ironed out had he stuck around. Over the years, I’ve blamed him for: being bad at football, not having a girlfriend, being bad at ballet, being bad at DIY, not having written a novel, not knowing what I wanted to do after university, being short tempered and not doing my tax return on time.

The other upside is having one member of your family who can’t ring up to complain about how they’ve been treated. My mum can phone, email and even tweet if she doesn’t like something I’ve said. If my dad wants to complain, he has to fork over 18 years of unpaid child support plus interest first, which is a considerable deterrent.

Freed from the chains of journalistic accuracy, I have used my father as a creative device to write about cuts to tax credits, the presidency of Barack Obama, the correct way to cook pasta and the merits of Harry Potter. Which is not quite as valuable as child support, but it is considerably more versatile.

That said, I’ve never written anything about my father that isn’t true. It’s just that how I feel about him, on any given day, is a reflection of what’s going on inside my head rather than a comment on a real, living person. Which is why it was something of a shock when I recently met the real, living person who is my father at Blackfriars Underground Station in London.

Well, “met” is perhaps putting it too strongly. The New Statesman office is near Blackfriars and I work in parliament at Westminster, so I spend a lot of time on the Tube. On one trip from the office to Westminster, I saw someone who looked eerily familiar. If you’ve ever spent five minutes staring at someone, trying to work out which wedding you saw them at, only to realise you’ve been eyeballing a weatherman, you’ll know the feeling: I stared at him for a few moments trying to work out if he had something to do with Brexit, before clocking that I’d seen his face on LinkedIn.

Then, just as you do when you realise that a terrified semi-famous person is wondering why a stranger is peering intently at them, I looked at my feet and walked past the man who had no idea that I was his son.

Why did I do that? Why didn’t I take what is – let’s face it – probably the only chance I’ll have to talk to my father? Because in that moment, I realised I had nothing I really wanted to say to him.

And the reason for this is: I’m happy. Happy in work, in love, and surrounded by my real family: a complicated network of friends, in-laws and the mother who stuck around. I couldn’t honestly have said I was angry with him, or I wished that he hadn’t left, because I’m happy with how my life worked out in the end.

But I don’t want to absolve him. He couldn’t know, close to 30 years ago, that the child he was walking out on would have the good fortune to be born into a country about to experience close to two decades of uninterrupted, low-inflation growth, most of that presided over by a Labour government firmly committed to improving the condition of the poor. (One of Gordon Brown’s forgotten achievements is that even after the financial crisis, child poverty continued to fall, because tackling it remained the government’s central mission.)

My father couldn’t know that I would benefit from investment in schools, museums and fantastic teachers, and the world’s best mother. But I did, which means that while a number of people – the taxpayer, society, my mum – have a legitimate grievance against my father, I don’t, not really. It worked out OK.

The dispiriting truth is that it might be different today: child poverty has increased every year for the past three years, even during periods of economic growth. Changes to the child maintenance regime have made it even harder to force absent parents to pay up, while the botched introduction of Universal Credit makes it more difficult for single parents in work to stay out of poverty.

And so I walked away from the man who was – or might have been – my father thinking this: I need to spend less time writing about an imaginary, lost parent, and more time writing about how much harder it is to be a kid like me today.