Amid headlines about the UK’s drought, Europe’s wildfires and impossible global temperatures, it was 28C when I arrived in Slough last Monday. I was there to look around Slough Trading Estate, a place that might once have conjured up images of the TV comedy The Office, many of whose laughs came at the expense of this overgrown patch of suburbia, 20-odd miles west of London.

But these days, this area of town – an incongruous mixture of old-school businesses such as Mr Clutch and Angling Direct, and vast, metal-clad leviathans that look like something pulled from JG Ballard – has become a byword for the constant expansion of datacentres, those hulking symbols of the vast computing power that big tech now requires, not least because of the ever-more complex workings of artificial intelligence.

In many people’s minds, datacentres are also a byword for the two totemic issues of yet another searing summer: heat and water. Across the world, the huge amounts of electricity they demand, mostly generated using fossil fuels, indelibly connects them to the climate emergency. The constant machinations of their crammed-in servers require cooling processes that also use vast amounts of water. So it is that the 21st century’s dominant means of communication intensifies our era’s most terrifying threats.

The first building I loitered around was a datacentre owned by the California-based company Equinix. There were 100 or so cars in its “visitor” and “staff” spaces, no corporate branding to be seen – and, up close, the constant sound of a low industrial whirr. On the other side of the street, poetically enough, was a set of offices occupied by Thames Water, a few of whose employees were taking a break outside. I pointed across the road: did they know what the building contained?

“There’s loads of AI bits in there,” said a twentysomething woman called Louise. “I saw something about it on Instagram: all the water they use.” She rolled her eyes. “It’s ridiculous. Loads and loads of........

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