Preparatory engineering work on the transmitter masts across the Border TV region will commence well in advance of 2008. Generally, this should not affect viewers other than a few short breaks in service outside peak viewing times. Some households who already receive poor reception may notice a slight degradation in picture quality during this time.
One month before the switchover date you will be able to check that the digital signal through your aerial is working when one of the existing services (probably BBC TWO) will be switched off in the Border region and replaced with some high power digital services including BBC TWO which will be available via your digital box or integrated digital television. So if you cannot already receive digital television this will be the time to acquire digital boxes and/or integrated televisions.
Approximately one month later analogue transmission of BBC ONE, ITV, Channel 4 and Five will be switched off and replaced by services carrying them in digital together with a number of digital only channels such as BBC THREE, BBC FOUR, ITV2, ITV3, ITV4, E4 and More4.
Source:-
http://www.digitaluk.co.uk