Airline bmibaby is being sued by the Royal National Institute of Blind People (RNIB) for allegedly "failing to ensure web access for blind and partially sighted customers".

"Bmibaby Ltd has failed to make vital changes to its website to allow customers with sight loss to use their online services instead of being forced to search for flights or make bookings via a call centre", said RNIB in a statement.

The charity said it had raised concerns with bmibaby in 2010 when RNIB was made aware of the problem through customers, no longer able to book flights through the bmibaby website.

RNIB said it had previously given the airline "expert advice" about the problem, had made recommendations, and had delivered a "full audit report" on the problem.

Despite this, said the RNIB, "bmibaby is still to make any significant progress. RNIB has now served bmibaby with legal proceedings as the website remains inaccessible to those using screen readers or those who cannot use a mouse".

Hugh Huddy, RNIB campaigns officer for inclusive society, said: "Why should those with sight loss risk missing out on a better web-only deal or be forced to ring a call centre simply because companies are failing to take accessibility standards seriously?"

A statement on the bmibaby website, presumably made before the legal action was served, reads: "Unfortunately our website is not fully accessible by people with sight problems, hearing, mobility and cognitive impairments. We are fully aware of this issue and are working alongside the RNIB to ensure our website is brought up to standard.

"We have received the RNIB recommendations and we are working to rectify the proposals. Whilst we are going through this process users can call 08451238951 (a local rate number) to access our fares at the original web price. We will aim to update this page on a regular basis to keep users informed of our progress and are working to rectify the issues as soon as possible."

Bmibaby has not yet provided comment.