Barclaycard has unveiled a new credit card that can add a contactless payment function to any phone, regardless of whether it is NFC-enabled or not.

Called Barclaycard PayTag, the device is a small chip-filled Visa card with a sticky back that attaches to the back of your mobile handset. Then, you can pay by just swiping the rear of your phone over a compatible terminal at any of the multitudes of stores and eateries that accept contactless payments.

The PayTag itself is free of charge to Barclaycard customers, and links directly to an existing Barclaycard credit card account. Users can currently spend up to £15 in a transaction, which will rise to £20 in June - just in time for the Queen's jubilee celebrations and the London 2012 Olympics.

It is roughly a third of the size of a conventional credit card and its placement on the back of a mobile phone means you are more likely to have it on you at all times. While the latest conventional Barclaycard credit card also features contactless payment technology, David Chan, CEO of Barclaycard Consumer Europe, believes we hold more stock in our mobile phones.

"[According to a recent YouGov poll] more than half of us say that the item we’re most lost without is our mobile phone, so we’re giving people the option of using them to make easy, convenient, everyday payments without the need to upgrade their current handset," he said.

Visa also predicts that the number of contactless point-of-sale terminals in the UK will rise to 150,000 this year, and research undertaken by Barclaycard indicates that £3 billion of purchases will be made with mobile phones in the UK in 2016. Even London Buses and the Underground will accept contactless payments by 2013.

Pocket-lint also got to try the PayTag itself, being given one to stick on to the back of a dummy mobile phone (in our case, a plastic representation of a BlackBerry). We were let loose in Eat, one of the many venues that are all teched-up already, and given up to £15 to spend on lunch.

We stuck the card on to the back - which is a panicky process itself, as the glue is pretty strong, so care is needed if you want it to look decent. And then paid for our bag of crisps, coffee and a cookie. Simple.

The best part of it is that, because it's linked to your existing credit card account, you don't need to top up your funds. It's also as safe as your existing credit card, with 100 per cent fraud protection. Plus, as you can pay only up to £15 at a time, it would be hard for a thief to run up exorbitant bills before capture/cancellation.

The only thing we could find fault in Barclaycard PayTag is that some people may not want to deface their phones permanently. However, they could always stick to the back of a phone case instead - jobs a good'un.

Initially, the PayTag will be offered to a select number of Barclaycard customers, with a mass roll-out coming later in the year.

What do you think? Would you be happy to stick a PayTag onto the back of your phone? Let us know in the comments below...