Leading terrestrial channels have come together for the first trial of high-definition digital terrestrial television in the UK, which will include BBC coverage of the World Cup and Wimbledon.

The closed technical trial is officially limited to a sample of 450 households in the London area. The BBC, ITV, Channel 4 and Five are contributing to the trial, which is initially expected to last for six months. It aims to test the technical aspects of delivering high-definition services to conventional television aerials.

The BBC HD stream is being transmitted by National Grid Wireless and the commercial multiplex is being broadcast by Arqiva, with technical support from Siemens and Thomson respectively.

It is possible to pick up the low-power MPEG-4 signals from Crystal Palace in south London in many parts of the capital, but they will not be viewable on normal Freeview boxes.

Receivers are being produced by consumer electronics companies Humax and ADB. They are being made available to 450 selected households in an audience research panel being conducted by TNS Media.

High-definition terrestrial television is already available in countries such as America and Australia, but the limited capacity within the available broadcast spectrum currently inhibits deployment in the UK.

Somehow the broadcasters seem to have found sufficient spectrum in the London area to enable the tests and no doubt support the lobby for high-definition terrestrial broadcasts in capacity released by switching off analogue transmissions.

Other possible and arguably more valuable uses for terrestrial spectrum include mobile video and data services.

The trial coincides with the launch of high-definition channels on the Sky satellite platform in the UK, with the World Cup expected to be a leading attraction.