London taxis united by One Number software

Users of black cabs in London are from today able to call a single number to get picked up.

The launch of the 0 871 871 871 0 'One Number' - backed by Mayor Ken Livingstone - pulls together the 7,000 of the capital's 21,000 cabs that are run by CallACab, Computer Cab, Datacab, Dial-a-Cab, Radio Taxis and Xeta.

The technology that allows the new system is called Vision, an information management package provided by Manchester-based Totem, and works by creating a virtual call centre - meaning calls are passed from one cab company to another on a rotating basis as calls aren't picked up.

Peter Gibson, head of corporate development at Radio Taxis, said the initiative marks co-operation between taxi companies who might otherwise have lost business to private hire minicabs.

"The software allows calls to be switched from one call centre to another - that was its unique selling point," he said.

The company had previously used Thus in isolation. The next stage might be for interactive voice response (IVR) systems, cutting down on the need for lots of call centre agents, said Gibson.

Typically radio or computer controlled taxis see rushes at certain times, for example when there is a train or tube strike or bad weather, but then cab companies traditionally favour those with set-up accounts rather than others wanting to pay by cash.

Livingstone's main aim was to provide a service that was easier for everyone to use, and to improve safety.