BBC HD on satellite and cable has been given a stay of execution while bosses consider launching a permanent hi-def service.

The BBC Trust will carry out a public value test on the BBC's proposal for an HD channel, and will keep BBC HD going until it publishes its findings on November 21, 2007.

BBC HD was due to close down at the end of May, when the year-long trial came to a close - now just the Freeview trial in London will finish because it only had a limited licence from Ofcom.

The PVT will launch on May 21, when the BBC Trust publishes the BBC management's full proposal and a request for Ofcom to study the HD channels effects on the TV market, and opens a consultation on the proposal.

However, the Trust has already stated that high definition will be essential to the success of Freesat, which is due to launch in early 2008.

There are currently more than 2 million HD Ready TVs in the UK, but BBC HD is the only free hi-def channel on satellite or cable.