People using Tubes, buses and trains in London could soon be using a new 'smartcard' instead of conventional tickets.

The new system was officially unveiled by the Mayor of London Ken Livingstone on Tuesday.

The scheme uses an electronic card to get through ticket barriers and on to buses.

Bus and Tube staff will use it for a trial period and it could be available to the public by next spring.

Card personalised

Martin Howell, from TranSys, told BBC London: "The card has got a microchip and aerial embedded in it.

"As you approach the gate you pass it over the reader and the gate will open, assuming that the card has been paid for and you've paid for your journey."

Transport for London (TfL), which is responsible for the capital's transport system, says it will be possible to top up the value carried by the cards with cash.

So they could also be used to pay for items at stations such as newspapers and confectionary or for the excess fare if the carrier goes beyond the London fare zones.

The card can be personalised so if it is lost it can be replaced and the system will know how much money and time is left on it.

Up to 80,000 people who work for London Underground and TfL are taking part in the trial period before it is introduced in the spring of 2003.