The BBC is to begin trial broadcasts of high-definition television (HDTV) in mid-2006 with what it calls "highlights of the schedule " made available to selected digital satellite and cable viewers.

HDTV is four times as detailed as conventional broadcasts. The BBC will also test the format on digital terrestrial TV in London. Viewers will need a compatible TV and receiver.

The trials, lasting a year, will test how HDTV broadcasts are transmitted and received and will not affect the reception of current channels.

The BBC did not reveal how many participants will take part in the trial, nor how they will be selected.

Although the corporation said that highlights will be shown during the test, it revealed that the current series of Bleak House and Rome have been made in HDTV. The BBC aims to produce all its programmes in the high-definition format by 2010.

BBC director general Mark Thompson stated that he would deliver free-to-air HDTV on all BBC digital platforms "as soon as practical", expected to be by about 2010.

Sky plans to launch an HDTV service in 2006, which will include live Premiership football.

The HDTV system is already available in Japan, Canada, Australia, South Korea and the US, and compatible HDTV sets are already on sale in the UK.

A BBC spokeswoman said there was a possibility that next year's football World Cup would be broadcast in high definition format as part of the trial.