O2 Wallet: Oyster card, Barclaycard and phone in one

Forget carrying around a separate mobile phone, credit card and Oyster card -- according to O2, in the future we'll only need one device. At a press conference this morning, O2 announced the start of a trial that will see 500 people test out a system called O2 Wallet.

O2 Wallet is essentially a mobile phone (in the trial it will be a modified Nokia 6131) that acts as an Oyster card and a credit card. Similar to Londoners' current Oyster cards, you simply have to tap the phone against card readers in Tube stations for it to debit the appropriate fare. Making payments for other goods and services is equally simple.

The concept isn't new and uses near-field communications (NFC) technology that's been around for some time, although this is the first time it's been trialled in the UK on this scale. NFC will also allow users to pick up downloads such as ring tones or wallpapers, for example, by simply tapping advertising posters with chips in them.

The trial will last for six months, after which all of the companies involved, including Transport for London, TranSys, Barclaycard, Visa Europe, Nokia and AEG, will decide what to do next. If the trial proves successful, we might see this system rolled out to the high street by the end of next year.

While we're impressed with the O2 Wallet's versatility, we're still uncertain of a few issues the system might bring up. Click on the next photo to find out what's got us a little concerned.