Three high definition Freeview channels will launch in the UK before the end of next year, Ofcom has announced.

The BBC, ITV and Channel 4 will each offer an HD Freeview channel over an upgraded terrestrial TV platform.

To be broadcast on the new DVB-T2 standard, current equipment will not be compatible so consumers who want to watch the higher-quality broadcasts will have to upgrade their set-up.

New set-top boxes will be on the market in time for the first step of the staggered roll-out, due to begin in the Granada TV area next year ending with London, Tynes Tees and Ulster in 2012.

Ofcom said a fourth possible Freeview HD channel would launch in 2010.