Ofcom said yesterday that broadcasters would need to monitor the wording given on their live shows every six months for two years amid concern that there were problems with the speed and accuracy of subtitles read by more than a million people with hearing impairments.
Companies will have to collect data on the number and type of errors as well as the subtitling speeds and the gap between the words being spoken and the corresponding text appearing on screen for viewers.
Delia Henry, director of Action on Hearing Loss Scotland, said: "Subtitle delays and accuracy are the biggest problems for television viewers with hearing loss as simple mistakes can change the entire meaning of a news item or interview.
"We welcome Ofcom's new requirement for broadcasters to measure the quality of their live subtitles as it could help to highlight problems and drive improvements.
"We urge broadcasters and subtitling companies to invest in live subtitling technology to make viewing accessible for people with hearing loss as it is for the rest of the population."
Ofcom said that pre-prepared subtitling on recorded programmes was "generally of good quality" but there was an issue with live programming, which was "prone to errors".