Paying for a pint with your finger: The tech that could kill off cards

Camden Market in north London. A swirl of people hunting for bargains, trends and photo opportunities. And amid it all is a chance to see the future.

In a bar called Proud is an unassuming gadget, sitting on the bar and linked to a small screen.

It is a finger-scanner, the sort of thing you might see in a hospital, but here it is not designed to measure your blood, but rather to pay for your drink.

This is the latest frontier in biometric payments, the ongoing battle to rid us of cash, cards, cheque books and other such accoutrements.

Instead, runs the logic, we will use the humble finger to pay for things, quickly and securely.

And that's where the finger-scanner comes in.

The layout of veins in your fingers is all but unique - the chances of you sharing that layout with someone else is 3.4 billion to one - so by analysing those veins, the machine can be pretty sure that you are who you say you are.

By linking the details of that vein pattern to a bank card, you can then close the circle. Instead of using a contactless card to pay for a round of drinks, you instead use your finger.

This is very clever technology, being used in a very small test, but so far it is working.

Regulars at Proud have signed up to the test and bought drinks, and the ones who spoke to Sky News seemed happy, partly because it was fast and reliable, and partly because of the novelty of using your finger to buy a round of drinks.

But can this become anything more than a novelty? The man behind trying to sell this technology to the world is Nicholas Dryden, the chief executive of the payments company Sthaler.

He told Sky News the technology would soon be rolled out for testing in supermarkets, cinemas and at music festivals.

"The supermarket trial is very important to us," he said.

"There are lots of applications, but what they want to know is whether you can replace a loyalty card with your finger. Lots of us forget our wallets when we go out. You probably won't forget your finger."

The concept of using your body to pay may seem a curious idea, but it is part of a trend.

Ever since the Romans first came up with basic cheques, people have looked at new ways to pay for products. From carbon paper to chip and pin.

It was only last year that just about all smartphones could be used as wallets. Now, biometrics. Your body as a bank card.

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It is a trend that intrigues the British Bankers' Association.

"In a few years' time, maybe 10 years' time, the way we bank could be almost unrecognisable from what we do now," said Chief Executive Anthony Browne.

"We'll have far more biometric security and far more convenient ways of paying - less cash, less cards, people just using their finger, or their iris to make payments."

It is an intriguing world, but there is one question that absolutely everyone wanted to know the answer to - so here it is. No, you can't just chop off someone else's finger and use that instead. It won't work in the scanner. So now you know.