Analogue TV is to be switched off between 2007 and 2012, meaning everyone in the UK must watch on digital TV. What are the full implications for viewers?
WHAT IS DIGITAL TV?
Digital technology converts TV pictures and sound into the "computer language" of 0s and 1s.
This allows them to be compressed - so many more TV and radio channels can be broadcast - and utilised in different ways.
A digital receiver - either built into the set, or in the form of a set-top box or adapter - gives the TV set some of the characteristics of a computer, enabling viewers to interact with programmes and read text on the screen.
WHAT IS ANALOGUE TV?
Analogue TV is the old system of broadcasting that we have had since television developed in the 1930s and 40s.
IS ONE BETTER THAN THE OTHER?
Many people say the digital system is better, providing better pictures, better sound, more TV and radio channels and interactive services.
But it cannot yet be received in some parts of the UK and reception can be less robust than analogue TV.
HOW CAN YOU RECEIVE DIGITAL TV?
More than 85% of UK homes (21.4 million) already have digital TV in at least one room, via cable (usually Virgin Media), satellite (Sky or Freesat), a TV aerial (Freeview).
Many viewers pay a monthly subscription for a range of channels, but a growing number of households are opting for free-to-air services, such as Freeview.
The BBC and ITV have launched a free-to-air satellite service, Freesat, which does not require a monthly subscription, while Sky offers its own free service, called Freesat from Sky.
Another digital platform uses broadband to deliver TV channels over the existing telephone network. Tiscali TV provides this, while BT Vision uses this to add additional services for Freeview viewers.
Not all digital platforms are available in every part of the UK, so how you get digital TV will depend on what is available in your area.
WHAT ABOUT HIGH DEFINITION TV?
Sky and Virgin Media customers with suitable TVs can pick up HD broadcasts, which offer crisper pictures, for an additional subscription.
The new Freesat service offers the BBC's HD channel - as well as the soon-to-be-launched ITV HD service. HD services on Freeview will be rolled out across the country from 2009 - although viewers will need a new set-top box to pick up the pictures.
WHEN WILL ANALOGUE TV BE SWITCHED OFF?
Whitehaven and the surrounding area in Cumbria was the first place to have its analogue signal switched off, in October 2007.
The Selkirk area, also part of the Border ITV region, will follow in late 2008.
The rest of the UK will follow, region by region, ending in 2012. The full schedule follows:
The exact date for the switchover in your area will be revealed six to eight months before it is due to happen.
HOW WILL THE SWITCHOVER HAPPEN?
The same process will be followed across the UK, transmitter by transmitter.
The analogue BBC Two signal will be switched off first in the middle of the night, followed about four weeks later by the remaining analogue terrestrial channels.
WHY DOES ANALOGUE TV HAVE TO BE SWITCHED OFF?
It is wasteful and more costly to broadcast the two systems alongside each other. Just as colour TV replaced black and white, digital TV is seen as the future.
But the main reason is that 25% of the UK cannot currently receive digital terrestrial signals through an aerial (Freeview).
When analogue is closed down, the frequencies can be reallocated to ensure almost universal coverage and a stronger signal.
The remaining frequencies can then be sold off for other uses such as mobile phones, mobile TV and high definition TV.
WHAT EQUIPMENT DO I NEED TO RECEIVE DIGITAL TV?
You can buy a digital television set, and a much wider range is now available in the shops.
These are called integrated digital sets and have the digital receiving equipment built in, either for Freeview or satellite. At the moment they are available from about £100.
But most current digital homes have a set-top box that turns their existing analogue set into a digital television .
Freeview boxes cost £15 upwards depending on their specifications.
Most people will be able to use their existing TV aerials to receive digital signals, though some may need to have new aerials installed to receive all the services.
You can check your postcode at www.freeview.co.uk or www.bbc.co.uk/digital.
Cable companies provide their own set-top boxes for a monthly subscription, with the option of a telephone and broadband service too.
For satellite TV, Sky provides a set-top box and satellite dish for a monthly subscription and also offers a free-to-air service for a one-off payment of £150.
The BBC and ITV have launched a free-to-air satellite TV service, requiring a one-off payment for a dish, set-top box and installation - but no monthly subscription.
WHAT IF I CANNOT AFFORD THE EQUIPMENT OR DON'T KNOW WHAT TO CHOOSE?
Equipment, installation and assistance will be provided to people over 75, those with severe disabilities and the blind or partially sighted.
This will cost £40, or those who are eligible and are also on pension credit, job seeker's allowance or income support will get it free.
About seven million households are thought to be eligible in total, with the BBC paying for the £600m scheme through its licence fee income.
HOW LONG WILL I BE ABLE TO USE MY OWN TELEVISION SET?
For as long as it still works, provided you hook it up to a digital set-top box or adaptor.
WILL I NEED MORE THAN ONE SET-TOP BOX?
You will need a set-top box for every TV you own. This could prove costly since many homes now have three, four or five sets. But the cost of digital receivers is coming down all the time.