17 April 2012 Last updated at 03:50 ET

London analogue TV signal to be switched off

Roadshows have been held across the city to assist TV viewers in making the digital switch

The analogue television signal in London is being switched off.

BBC One, ITV1, Channel Four and Channel Five stopped transmitting on analogue overnight. The BBC Two signal was stopped earlier this month.

It means people will need to convert televisions to receive the digital signal and Freeview viewers also need to retune.

An estimated 12 million viewers are affected in the London area, but most homes have already switched to digital.

Roadshows have taken place throughout the city to help people who are yet to make the change.

Advice points, run by volunteers, are also available in local communities and there is a hotline for people who want information.

To mark the switchover the Crystal Palace transmitter, in south London, will be lit up on Wednesday night with 200,000 watts of energy efficient lighting at a ceremony attended by Sir David Attenborough and DJ Chris Evans.

Television broadcasts in London have come from the tower since 1956.