Bank transactions made through a mobile phone will soon become possible for the first time in the UK.

The Link cash machine network is behind a new service that will let subscribers check a bank account balance and buy mobile phone minutes using the phone itself.

Link will also introduce some cash-machine functions on through a downloadable application, called MobileATM. Initially, this will provide account balances and soon after let users add time to a pre-paid phone account, according to technology partner Sun. It should work on any mobile network that allows subscribers to download third-party applications.

At the 3GSM Worldwide Congress in Cannes today, Sun will tout its participation in the project - the latest to use Java software and SIM cards to certify that users are who they say they are. Sun is promoting Java as an ideal technology for secure transactions. "Identity is a valuable asset that the carriers have that they are underutilising," said Eric Chu, director of Sun's J2ME last week.

The SIM card that comes in every GSM phone has nearly unbreakable security, and combining that with Java software can form a trusted platform for customers to authenticate their identities before carrying out tasks such as cash-machine transactions, said David Rivas, chief technology officer for Sun's client systems group. The applications can run on a Java virtual machine on the phone, which is secured via a "sandbox" that keeps viruses and other problems out of the software, he said.

The technology offers a number of possibilities, Rivas said. For example, subscribers could start up their phones with a password and then use it, via RFID or another technology, to pay tube fares wirelessly, Rivas said. Even more significant, for larger purchases the phone could act like a credit card, with a Java application popping up a screen for the subscriber to enter a password on the spot, and the phone communicating the authorization to a cash register, Rivas said.

The service was scheduled to be launched last month with a global introduction later in the year.