Traditionally, with signed programmes, you see a picture of a person signing in a corner of the screen. This is called open signing.
Very few programmes are signed and these are generally shown as repeats late at night. Yet over 50,000 deaf people in the UK use British Sign Language (BSL) as their first language.
Ofcom sets and monitors targets for broadcasters. The current 10-year target is for 5% of programming hours to be signed. This excludes commercial channels with less than 1% of audience share which have a target of 30 minutes per month. Broadcasters are also required to raise awareness of this service and to identify signed programmes with 'SL' in on-screen TV Guides.
Today, if you go digital, you will still get just a few signed programmes. One of the problems is that open signing is expensive to produce, requiring a signer to be filmed separately from the programme. And, of course, non-users can find it intrusive on the screen.