The historic switch from analogue to digital television is being celebrated this evening with a special light show.
The Crystal Palace transmission mast will be illuminated in what organisers are describing as an 'explosion of light'.
The analogue television signal has been switched off permanently in London from today. That means you will either need a digital television, a digital set-top box, cable or satellite services in order to receive a signal.
All digital television users will also need to re-tune their sets today. Further details can be found on the Digital UK website.
The light show will begin at 9:15pm tonight.
The analogue signal has been switched off for good in London.
The historic event will be celebrated tonight with a spectacular lightshow at the Crystal Palace broadcast tower.
For more than 50 years the Crystal Palace tower has broadcast to more than 12 million people in the Greater London area and surrounding counties.
In a week's time you could be watching TV and your screen will just go blank. Digital UK is warning that a million homes in the capital still rely on the old analogue signal. The digital switchover happens from Wednesday April 4th 2012. The change is made from a transmitter in Crystal Palace.
Digital UK has warned more than a million TV sets risk going blank when the London region begins the switchover in a week's time.
More than one in ten households still have a television relying on the old signal, amounting to more than a million TVs in the region.
The digital switchover replaces the existing analogue TV signal with a digital signal.
The first analogue channel to go is BBC2 on Wed 4th April; the remaining four, including ITV1, disappear on Wed 18th April.
Deborah Bain, London Manager for Digital UK, told ITV News: "If you're watching one of those [analogue] televisions, you need to do something or you will be left with a blank screen.
"You can convert your television with a digital box, satellite or cable services.
"It is really important if you already have Freeview you do a full retune on the 4th of April and then again on the 18th of April."