A window between cities that allows people hundreds or even thousands of miles apart to meet and talk could make its debut in Britain next year.

Tholos, named after a type of circular ancient Greek temple, consists of a large round screen nearly 10ft high and 23ft wide.Its designers hope to see one of the first two in the world become a new tourist attraction in the centre of London.The London Tholos would be linked to an identical one in Vienna. Through them, people in both cities will be able to see and hear each other in real time.The cylindrical structure contains technology that simultaneously transmits and receives high definition live moving images.

People standing in front of London's Tholos would see a wrap-around picture of the scene in Vienna. At the same time, a similar London image is displayed in the Austrian capital.Citizens in both countries would be able to face each other and talk via an array of directional microphones and loudspeakers, which keep conversations private.Effectively, it is like meeting up in the town square - except that you might be on different continents.

Given the necessary sponsors and planning permission, Tholos screens twinning London and Vienna could be up and running by the second quarter of next year.

There are ambitious plans to expand the system into a network linking at least 16 European cities by 2008, and then others in North America and Asia.

Each Tholos is expected to cost about 1.4 million to build and install. Public access would be free, and running costs paid for by advertising, which will take up 13% of airtime.

Screenshot: Tholos

Ananova