The regulator has drawn up a timetable for the national switch-off of the analogue terrestrial TV signal and the conversion to a fully digital TV system.
In 2008, the first regions to be hit will be Border, Westcountry and HTV Wales. This means that viewers that don't have either Freeview, Sky or digital cable TV will be left without television.
The following year, Manchester and Scotland will also be forced to upgrade to digital TV, while the Central, Yorkshire and Anglia regions will follow in 2010.
The London region will be one of the last to see its analogue signal switched off in 2011 along with the Ulster, Meridian and Tyne-Tees regions.
Channel will be the last in 2012.
Ofcom acknowledges that there are viewers who are not willing to convert to a digital TV set. Because of this, the switchover in each region will take six months, to give them time to reconsider.