O2 has outlined its plans to bring the hugely popular Japanese mobile phone technology i-Mode to the UK. Due to launch in time for Christmas this year, i-Mode will be O2's answer to the likes of Vodafone Live, and will allow customers to buy content and services via their phone bill or prepay balance.

In Japan, that means downloading ringtones, games, cartoons and music, and activities such as share trading, buying tickets and subscribing to premium information services.

Jag Minhas, O2's chief i-Mode architect, says that the system's big advantage over WAP-based data services is consistency and ease of use. Every handset will have the same basic applications, and the i-Mode main menus will be stored on the handset to save connection time.

"The technologies are not proprietary, but the processes are tightly specified and geared to giving a good customer experience," he says. "We are trying to avoid the scattergun approach we had with WAP settings." He adds that the aim is to make data services as simple to use as voice.

Minhas says that a big advantage of i-Mode is that it uses a derivative of HTML - formerly cHTML but now XHTML - making it relatively easy to repurpose an existing website, with the handset resizing images and pages as needed. It also relies heavily on Java, in NTT DoCoMo's DoJa variant, and some handsets will support a Macromedia Flash.

However, there could be compatibility problems, as i-Mode operates differently to other mobile data services, warned Paul Danter, solutions head at mobile services developer Argogroup. "With other i-Mode operators there isn't necessarily interoperability between ordinary MMS and i-Mode MMS - i-Mode is very e-mail-centric," he says. "Plus it doesn't remove the need to develop your service in other formats for other operators."

Another challenge for O2 is that i-Mode requires all-new handsets, and because the menus are pre-loaded, those handsets can only be used on O2. Minhas says all the major manufacturers are developing i-Mode devices; but O2 still needs to get those into users' hands.

Several other European networks are already offering i-Mode services, for example Bouygues in France, E-Plus in Germany and Wind in Italy, and they say that on average monthly revenue per user has risen by 6 to 10 Euro (£4 to £7). O2 has exclusive rights to i-Mode in the UK and Irish Republic; its German operation will use the technology too, but under a different name.

Content providers will need to sign up with O2 but will then receive the bulk of the fees paid by the customer, the company claims. O2 will charge a commission, plus fees for the GPRS traffic consumed. O2 is acknowledging here that its strengths lie not in content provision, but in delivering data and using its relationship with the customer to provide microbilling capabilities.

Minhas says there are opportunities for business use too, either in terms of business to business sales, or for a company to enable its intranet for i-Mode access. The service will also provide e-mail to the phone with push notification of new messages, although not access to Internet e-mail accounts - effectively it is text messaging to and from e-mail accounts.