Cash? I couldn't see the point. I had a few tenners in my wallet, and a bulky zipper section crammed with pound coins and shrapnel.

I tried to get rid of it in cafes, corner shops and the like, and they didn't want to know.

“Sorry, cards only,” the assistants told me.

My daughter is a student and forever short of money, so in a fit of generosity, I emptied my wallet on her.

She seemed grateful, and so was I with my new slimmed down wallet.

I was joining the 21st century and becoming completely cash free. And I couldn't have picked a worse time.

There's been a huge global push to replace cash with digital payment methods.

Governments love the idea, because cash is hard to trace and can be used for criminal activities such as money laundering and taxation.

By contrast, electronic transactions create an audit trail.

Cash still made up more than half of all payments in 2013. Now it’s less than one in 10. But as we've just discovered, the cashless society can quickly come unstuck.

This week's blackouts in Spain and Portugal have put digital money in a very different light. Without power, it's completely useless.

In an emergency, cash is still king.

Need to buy food when the power is down? Or water? Baby food? Want to take a taxi because the trains are out?

Europeans who tried to do these things were all given the same answer: “Sorry, cash only.”

In a crisis, only cash will cut it. Cards are just a useless slither of plastic. It could be even be a matter of life and death.

And as for digital currencies such as Bitcoin? Forget it.

Doom-filled "preppers" reckon if society collapses, their pile of crypto-currency will be king. They're deluded.

It’ll be cash all the way. Or cruder forms of barter.

The same goes for gold. It's the oldest store of value and its price rockets in a crisis, as we've seen lately. But you can't exchange a gold bar for loo roll.

Well you probably can, but you'll regret it when the lights come back on.

These days most investors buy gold on the internet anyway, so don't physically own it. Without power, digital gold is worthless.

Our politicians have only just woken up to the danger.