Fancy a chip attached to your fingernail to let you pay for goods in shops? Or a tattoo on your hand that lets you wave and pay when boarding a bus or train? Or giving your bank a print of your retina, so all that’s needed is a scan of your eye? These are just some of the ideas being studied by Barclaycard and Visa as the contactless spending revolution continues.

More immediately, the first car keys to have a contactless Barclaycard chip embedded in them were launched this week with DS Automobiles, part of Peugeot-Citroën.

Fitbit, the exercise tracker, also this week introduced a band that incorporates a contactless payment chip. With the Ionic tracker, due to go on sale next month, cardholders will be able to pay with Fitbit Pay. Meanwhile, on Thursday Visa also announced a partnership with Garmin, perhaps best known for its satnav and GPS products. Its Vivoactive 3 smartwatch will allow wearers to be able to pay via their watch.

This month is the tenth anniversary of contactless or “touch and go” payments in the UK, and banks and payments companies are researching ever-more adventurous ways technology could be used to make it even faster.

Tami Hargreaves, head of partnerships at Barclaycard, says: “Half of shoppers aged 25-34 would be open to alternative forms of contactless payments, such as retina scanning and contactless chips embedded in their palms and/or fingertips. This makes them the most ‘forward-thinking’ age group when it comes to contactless technology.”

“Wearables” such as bracelets and watch straps fitted with contactless chips are already available, while there have been trials of wave-and-pay beer pumps, scarves and hats, and – this month – a contactless ice cream van allowing aficionados to pay for their Mr Whippy in just 60 seconds.

Trials are essential to weed out problems – Visa put contactless chips into sunglasses but the problem was they were too easy to lose.

At first a sceptical public was slow to embrace the idea. But contactless accounted for over 39% of all Visa face-to-face payments in Europe in April this year, up from 11% two years earlier.

This summer Visa hosted the UK’s first contactless music festival, BoardMasters, where every retailer was offered the chance to go contactless, cutting queues and thus waiting times.

Barclaycard is forecasting that spending this way will soar by more than 300% over the next four years as seven in 10 Brits begin to use it more frequently for everyday purchases. Its research indicates that almost six in 10 of us now use it, with 71% saying they choose to pay this way more frequently than 12 months ago – indicating a more recent spike in popularity. Just last month, debit cards overtook cash to become the number one payment method, according to data collected by the British Retail Consortium, with growth in contactless a prime driver behind the rise to dominance of the plastic card.

Half of shoppers age 25-34 would be open to retina scanning and contactless chips embedded in their palms or fingertips

Despite all this, half of retailers are yet to adopt the technology. Not all major names, including John Lewis, have done so – to their cost. Barclaycard says that businesses that accept contactless report the number of such sales rising by an average of 30% a day, with uptake increasing fastest among over 60s.

But it’s not all about payments. At the Internet of Things Watson research centre in Munich, Visa is working with IBM to develop ways of using the technology to alert drivers when a car’s warranty or certification is about to expire, or if specific car parts need replacing. With this information the driver will be able to order parts with the push of a button, or schedule a service appointment.

But Shashi Verma, chief technology officer and director of customer experience at Transport for London, who oversaw the original introduction of contactless payments for Oyster (the largest smartcard-based ticketing system in the world) in conjunction with Barclaycard, believes that wearables have limited attraction for consumers, and that card payments are a more secure and robust system for the longer-term.

Popularity stakes

· The Czech Republic leads Europe in terms of uptake of contactless payments, with usage of more than 85%.

· Slovakia and Poland are in second and third place respectively, with usage in excess of 66%.

· UK penetration currently stands at more than 42%.

Source: Visa. All figures for April 2017