The RNID is campaigning for greater access to BBC Parliament, writes Nathalie Thomas.
The RNID is working with the shadow minister for disabled people to put pressure on the Government to put more subtitling on the BBC Parliament channel.
The charity is arguing that limited subtitling on the channel is denying disabled people access to the democratic process.
It is lobbying Jack Straw, leader of the House of Commons, and Mark Thompson, director-general of the BBC, with the help of Jeremy Hunt, the Conservative MP for South West Surrey.
"Everyone deserves to have access to democracy, but there are many people who are currently denied that right," said Hunt.
At present, the BBC provides two hours of subtitling on its parliamentary channel. According to the RNID, however, this often means disabled people are excluded from debates that could affect them.
The subtitles are limited to the first two hours of sitting each day, but critics say this denies those with hearing disabilities the chance to watch some of the more interesting and important debates.
"A topical example would be 4 May, when there was a whole day of debate on disability," said Mark Morris, head of parliamentary and European affairs at the RNID. "The debate lasted for about six hours, but only a fraction of it was accessible."
The RNID and Hunt have already had one meeting with the BBC Parliamentary team. But they are yet to receive a response to a letter, addressed directly to Thompson, that was sent five weeks ago. In the letter, they argued that full subtitling on the channel falls under one of the six key principles to which the broadcaster must adhere under its new charter - namely, to sustain citizenship and civil society.
BBC Parliament is a 24-hour channel whose low average viewing figures render it exempt from Ofcom regulations on subtitling and signing. But the RNID argues that it should be treated differently because of the important subject matter it covers.
"It provides access to the democratic process," said Morris. "This is one channel that shouldn't be subject to the same criteria as everything else."
Hunt and the RNID have also requested a meeting with Straw, who took over as leader of the House during the Cabinet reshuffle earlier this month.Their hope is that Straw will be encouraged to act because his predecessor, Geoff Hoon, had already expressed support for the campaign.
In a statement, the BBC said: "The subtitling team provides two hours of live subtitles a day, and BBC Parliament is the only parliamentary channel in the world to provide this service.
"Our viewers with hearing difficulties also want to see subtitles for programmes on the other BBC channels. Our resources are finite, so we allocate our subtitling service to reflect the BBC programmes that people want to see."