At some point between 2008 and 2012, "digitalswitchover" will happen to each and every television set in the UK.
Since television was introduced in the UK in 2nd Nov 1936, it has undergone two significant changes: the change from 405-lines to 625-lines in the 1960s and the addition of colour in the 1970s. All these systems are today called "analogue" because to describe the way the pictures are sent from the broadcaster's studio to the transmitters and onto the television sets.
For many technical reasons, it was only possible to provide five UK-wide television channels.
On 15th Nov 1998 new digital television services were added to around 80 of the UK's transmitters. By using computer technology (hence "digital television") is now possible to carry up to eight television channels in full colour with stereo sound in the same "space" that a single channel takes with analogue.
Because you don't need a contract to watch this digital television, it has been called "Freeview".
Unlike the two historic changes listed above, it is not necessary to buy a new television set to use these new digital "Freeview" channels.
However, if you happen to watch your television from the 1074 smaller transmitters, you do not have this option. The only way to extend the benefits of digital television to everyone is to switch the analogue signals over to digital transmissions.