BBC One, ITV1, Channel Four and Channel Five stopped transmitting on analogue overnight. An estimated 12 million television sets are affected in the London area, but most homes have already switched over.
The process to turn off the transmitter began at midnight on April 18th, when BBC director general Mark Thompson turned off the switch. The switch means people will need to convert televisions to receive the digital signal and Freeview viewers also need to retune.
To mark the switchover the Crystal Palace transmitter, in south London, will be lit up for 48 hours with 200,000 watts of energy efficient lighting.
Television broadcasts in London have come from the tower since 1956. The first regular TV service began on November 2nd 1936 when the BBC broadcast from Alexandra Palace.