Channel 4 subtitles and other services not likely to return until mid-November

Channel 4 subtitles, signing and audio description are not likely to return on TV until mid-November, almost two months after a catastrophic fault.

The outage, which has already lasted more than three weeks, has angered deaf, hard of hearing and visually impaired viewers.

More than 500 people have complained to broadcasting regulator Ofcom.

The fault happened on 25 September when a fire suppressant system destroyed hard disks at a broadcast centre.

An emergency back-up subtitling system also failed. The channel is building a new system from scratch, and said it will fix the problem more quickly than its current prediction of mid-November if it can.

The incident at the broadcast centre owned by Red Bee Media also affected other broadcasters like the BBC and Channel 5, although their services have now been restored.

"Channel 4 would like to apologise to viewers for not currently being able to provide access services," a statement said. "We realise how frustrating this is for our viewers."

The broadcaster will begin to offer subtitles for its biggest shows like The Great British Bake Off and Gogglebox on its online catch-up service All4 from this week.

However, the channel cannot provide audio description or sign language services at all. "These services were irretrievably lost during the incident and we won't be able to restore them until we move to the new system we are building," it said in an update published on Tuesday.

It added: "We cannot rush this and run the risk of something going wrong. Something like this needs to be installed slowly to ensure our channels don't come off air and to prevent something like this happening again.

"That means that full access services might not be available until the middle of November. Clearly, if we can do anything to speed up this process, we will."

Mark Atkinson, chief executive at hearing loss charity RNID, said: "For more than three weeks, the 12 million people in the UK who are deaf or have hearing loss have felt excluded and increasingly angry, because the system to provide subtitles and signed content is broken.

"It's impossible to imagine a failure that affected the hearing community being allowed to go on for so long.

"The BBC and Channel 5 are now offering a near-normal service, but it is unacceptable that the system could have failed so spectacularly, and that Channel 4 have still not fixed the problem. Further, there was a failure across the board to communicate to deaf people regularly and - most importantly - accessibly.

"We're pleased that Channel 4 have started providing updates in British Sign Language to the deaf community. They must ensure deaf people and people with hearing loss are kept informed about what steps they are taking until the problem is fixed."

An Ofcom spokesperson said: "We remain extremely concerned by the impact on people who rely on these services. Channel 4 did not have strong backup measures in place, and it should not have taken several weeks to provide a clear, public plan and timeline for fixing the problems.

"We now expect Channel 4 to meet the timings it has set for restoring these vital services."

A spokesman for Red Bee Media said: "Things are improving every day and we are able to deliver more and more accessible programmes, but we are unfortunately still experiencing issues with receiving the media for which our access teams create pre-recorded subtitles, audio descriptions and signing.

"As soon as there are any more updates, we will share these."

The original fault temporarily took Channel 4, Channel 5 and S4C off air completely, and led to transmission problems in the subsequent days, such as E4 being forced to delay the Married At First Sight series finale.

On 8 October, presenter Adam Hills addressed the problems on Channel 4's The Last Leg, holding up a hand-written sign reading "Sorry there's still no subtitles", followed by another saying "Sort it out".

The Times reported that the fire suppression system at Red Bee's headquarters sucked all the oxygen out of a room, causing a "sonic wave" that shut down the transmission servers.

A spokesperson for the London Fire Brigade said: "Firefighters were called to reports a gas suppression system had activated at a building on Wood Lane in White City on Saturday 25th September.

"The suppression system had activated in a server room and on site engineers worked to ventilate the room. Firefighters carried out a search of the building and a sweep of the room but found no fire apparent."