An illuminating and sometimes alarming book, Dreamers: How Young Indians Are Changing the World, is published this month. About 600 million people, more than half India’s population, are under 25 years old; no country has more young people.

“No matter how poorly placed they find themselves now,” writes the book’s author, Delhi journalist Snigdha Poonam, “they make up the world’s largest ever cohort of like-minded young people, and they see absolutely no reason why the world shouldn’t run by their rules.” The effect, Poonam says, will be to “change our world in ways we can’t yet imagine”.

One morning a few months ago it slightly changed mine. The landline next to my desktop rang, and a young-sounding man told me he was calling on behalf of BT Broadband. He gave me his name, an office address in west London, and what he called his ID number. “There seems to be some trouble with your server,” Philip (ID 45562) said. “We’d like to send someone to have a look. Will you be at home around four today?”

Nobody need tell me how wrong this sounds. I said yes, almost for the fun of it. “But before our engineer comes,” Philip said, “there’s a few things we can do to your computer … to help him get started. I’m going to put you on to my supervisor, Robert.”

Robert came on and also announced his ID number. I noticed he spoke English with an Indian inflection. Was he Indian? “No, I’m calling from London.” But perhaps he was born in India? “My mother is Indian.” Oh, from where? “Mumbai.” Which part of Mumbai would that be? He put down the phone and seemed to talk to somebody. “Andheri,” he said eventually, naming a western suburb, “but I’m here to help you, not answer personal questions.”

Feeling slightly reprimanded, I allowed him remote access to my computer. Why, oh why? I blame a heady sense of curiosity: to find out how he proposed in the end to cheat me.

The route was complicated – various exercises in which he demonstrated how my machine was being “cleaned up” – until he came to the sting itself. Many BT customers had had my problem, Robert said, so BT had agreed to compensate them all equally with a sum of £200, promptly payable online just as soon as Robert’s team could access my bank account, the homepage of which now appeared as if by magic on my screen and innocently awaited its password.

“I don’t want the £200,” I said more than once. “But the compensation is company policy,” Robert said. “As an employee, I can’t not give it to you.” He began to shout, “You have to take it, you have to take it … if you don’t take it I’ll mess up your computer so that it never works again. You have to take it!” His calm authority, all his fisherman’s patience at playing the fish, had given way to furious despair.

At a stop-off on his first voyage to India, VS Naipaul noticed from his ship in Alexandria that the line of old-fashioned horse cabs waiting on the quayside never took a fare; that however much their drivers harassed and pleaded with them, the tourists from a visiting liner went away instead by taxi and motor coach. To Naipaul, the pitiful scene of neglectful tourists and desperate cabmen showed that “there could be no pride in power”. I remembered that as I put down the phone.

When I spoke to BT, I was told that my experience wasn’t uncommon. Did my caller sound at all Indian? BT has closed one of its operations in India and some former call-centre staff might well be working a scam with stolen customer lists, which as well as making money offered the chance of revenge.

That seemed plausible. More recently an extract from Poonam’s book in the Guardian suggested another possibility: that the lists had found their way to a business devoted to scamming, such as the one in Mumbai where hundreds of youngsters were arrested for posing as US officials working on behalf of the Internal Revenue Service. They defrauded American taxpayers out of millions of dollars by reading from a six-page script that began: “My name is Paul Edward [the names were variable] and I am with the Department of Legal Affairs, with the United States Treasury department. My badge ID is IRD7613 …”

According to Poonam, entire districts of one or two cities are devoted to call-centre scams. The work has its attractions – one of them is outsmarting foreigners who believe they are smarter, as well as richer, than you are – but the main driver of recruitment is push rather than pull.

The sheer number of young people has yet to become an asset: only 2.3% of the Indian workforce has had formal training

Secure work is hard to find in India. In 2016, for example, more than 1.5 million people applied for 1,500 vacancies with a state-owned bank; more than 9 million took entrance exams for fewer than 100,000 posts on the railways; and more than 19,000 applied for 114 jobs as municipal street sweepers. The sheer number of young people has yet to become an asset: only 2.3% of the Indian workforce has had formal training in skills (compared with 96% in South Korea) and less than a fifth of Indian graduates are immediately employable.

Poonam estimates that to create millions of productive jobs and “call the shots in the global economy” India would need to build at least 1,000 universities in the next 10 years and nearly 50 times as many technical colleges. (This is the main reason that the British export the Indian government most values is the university place and the student visa.)

In the meantime a fervid self-helpism has grown among what Poonam calls “the provincial masses”. In under-noticed towns and non-metropolitan cities – there are echoes here of the recent political surprises in Britain and America – a generation is coming of age that combines the cultural values of the traditional Indian family with the life goals of the American teenager, “money and fame”.

In one such city, Indore, she visits the ninth-floor offices of WittyFeed, a successful viral content farm where nobody who attends the editorial conference is over 23 but where “a week is all it takes [for new recruits] to go from not knowing anything about the world to deciding what the world should know”.

People who have never left India work late into the night to tickle the English-speaking world’s sated curiosity. Clickbait: “Fourteen secret confessions by horny girls”; “What happens to your poop in an airplane toilet will leave you surprised”; and so on.

I visited Indore 35 years ago, before it had ever seen a shopping mall or heard of a listicle or knew that viral keywords included “terrifying”, “shocking” and “inspirational”. My train arrived at dusk and stopped at a signal just outside the station, where a train on an adjacent track also stood whistling and blowing off steam. Men in loose cotton clothes lay against the open windows of the carriages and smoked the cheapest brand of Wills.

The locomotive and the cigarette: transfers of technology and pleasure were apparent then as now, but nobody could have imagined what was to come.

• Ian Jack is a Guardian columnist