Miles Kington: There are times when I am glad I don't own an iPod

When you find yourself talking to a friend who doesn't even realise you are talking to them, you realise how much it makes the wearer miss

One of the things I didn't know about Sir John Betjeman until I listened to Doubts and Demons on Radio 4 on Monday, was that in his early days he hated the radio and its influence. All that cheap dance music. Filling people's ears. Stopping them listening to the natural world around them...

When he said that, radio was a new-fangled gizmo which must have seemed very pervasive. It still is very pervasive, of course, as you will know if you have ever had the builders in, but I think that if Betjeman were here today, it's the personal stereo and the iPod which would seem the enemy of the outside world and get his goat.

Clamped inside those headphones, people really are cut off. When you find yourself talking to a friend or family member who, you suddenly realise, doesn't even realise you are talking to them, so absorbed are they in their earphones, you realise the power of the secret sound source, and how much it makes the wearer miss.

I was glad the other day that I do not own an iPod and thus was not prevented from doing a bit of eavesdropping in a train out of Paddington. There was a family of four sitting opposite me, a mother and three sons. The oldest boy must have been about 16, and was trying to read the slim Penguin paperback by Niall Ferguson about the causes of the First World War: 1914: Why The World Went to War. He wasn't having a great deal of luck, because the other two boys, aged maybe 12 and 10, were larking about and having a great, if distracting, time.

The older boy would concentrate for a little while, then get drawn into their games, which at one point involved tearing up bits of paper and sticking them to your face to simulate different kinds of beard and whisker. At one point, I remember, the smallest boy stuck a thin bit of paper to his chin so that it drooped down, and stroked it, saying "Goatee... Goatee" in what he hoped was a deep voice.

He was called Archie, and, though the youngest, seemed also to be the funniest of the three, putting on lots of voices and pretending to be different characters. For a while, for instance, he pretended to be reading his own book, putting it up close to his face and intoning over and over again: "I am going out of my mind... I am going out of my mind..." which seemed an unusual and quite comic thing for a 10-year-old boy to say, especially as he didn't think anyone was listening, least of all the old codger across the aisle.

The mother, a nice-looking woman but with a tired look about her, and no wonder, was reading a book the whole time and never got drawn into her sons' goings-on except when she suddenly turned to the oldest boy and said: "So, what caused the First World War, then?"

"Well," he said looking a bit taken aback, "there was this German prince and he... no, hold on..."

"Honestly," she said, "what's the point of buying you books if you won't read them..."

"I am reading it!" he said. "I've nearly finished it. Look..."

And he pointed to the page he had got to. Mother looked unimpressed. Then the middle son decided to make trouble for the older.

"Mother!" he said. "He's just mouthed to me that he hasn't read it! He was lying to you!"

"You're the one who is lying!" said the older, and tried to beat up the middle one across the table, to the amusement of Archie and the annoyance of mother...

I was sorry when I had to get out and leave them. They were wonderful entertainment and a lovely bunch. So I asked my companion, when we reached the platform, if he had heard any of the conversation of the three boys and the mother.

"What three boys?" he said.

He had not even registered their existence. He had been listening to his iPod the whole time.