From today, 500 regular London transport users will be able to pay for their journeys using a mobile phone.

The system combines their existing Oyster travelcard with an O2 "wallet" on Nokia phones that will allow customers to make small cashless payments with their handset.

The six-month pilot scheme is the largest UK trial of near-field communications technology on mobile phones.

Co-operation between different suppliers will be vital, according to O2 UK commercial director Cath Keers.

"Without other mobile operators and financial instituations, this could not become a reality," said Keers.

"For this to work we will need the whole ecosystem to come together.

"If we get this right we can place the UK at the forefront of technology innovation," she said.

Commercial launch of the service will depend on the success of the trial.