But this is not to say that small changes cannot make an immediate difference. For example, adding meaningful alt tags to describe images makes life easier for people using screen-readers and requires very little outlay. The same applies to ensuring text can be resized in browsers and that colours can be changed. This is useful not only for people with dyslexia who can have problems reading black text on a white background, but also for those with red and green colour blindness.
The next step, meanwhile, is to create an action plan, bearing in mind that large companies in particular have complicated sites that cannot be upgraded all at once. "It's not reasonable to expect to fix everything in a month. Sorting out large websites with complex back-end systems will take more like two or three years," says Moss.
Accessibility requires a rethink of how web teams operate to make it a sustainable proposition. Coders and designers need to be trained to understand and implement the relevant concepts or expertise has to be brought in from outside. Procedures have to be introduced to ensure new additions to the site do not result in the organisation going back to square one.
Content must also be comprehensible and structured for easy reading. This necessity is often forgotten, and involves encouraging editorial staff to follow web-writing guidelines, which include breaking text up into manageable chunks and introducing only one idea per paragraph.
Accessibility also requires buy-in from senior management to motivate the workforce and counter any resistance to change, and this is where budgets can be an issue. Christopherson indicates that organisations can expect to pay a supplement of between 2 and 5 percent to ensure accessibility. These extra costs are likely to accrue from the need for more hand-coding, because "someone might not be able to use their content-management system in a completely Wysiwyg way", and because of the imperative for qualitative testing using real people with disabilities.
While automated tools can check for compliance against some of the WCAG checkpoints, according to Alun David, managing director of consultancy Linktec Solutions: "They can't check everything by any stretch of the imagination, much less than 50 percent" and therefore need to be supplemented by real-world testers.
As to where IT managers can go to obtain help and advice when embarking on a project of this type, a good place to start is the DRC website to download a free copy of the PAS 78 guide to good practice in commissioning accessible websites.
The DRC asked the British Standards Institute to create the specification, which was written earlier in the year by Julie Howell, former digital policy officer at the Royal National Institute for the Blind, and was peer reviewed by a steering group.
"It's about trying to fill a gap. There's ignorance out there on the technical side, but the people commissioning websites know even less and they're the ones that are legally liable," says DRC's Beesely. "You can never say that if you follow the guidelines to the letter, you'll be fire-proof, but if you do, you'll be way ahead of the pack."
Other places to go for help include the Guild of Accessible Web Designers", a global association of accessible web designers and developers who promote accessible web design standards, and the Association of Accessibility Professionals. This is an industry-based working group that is developing an accreditation scheme for website design organisations.
Despite the effort creating an accessible website entails, however, there are huge benefits to be gained from going down this route. In addition to addressing legal obligations and meeting growing ethical and corporate social responsibility concerns, the DRC points out that obtaining a single A performance rating has the bonus of increasing mainstream usability by 35 percent.
But there are other important commercial advantages. For example, Legal & General experienced a 95 percent increase in online sales following its revamp, which cost a comparatively meagre £200,000. This revenue boost, combined with reduced maintenance fees, meant that the financial services giant achieved a return on investment in only five months compared with the 12 months it had expected.
The jump in sales, meanwhile, was likely to be brought about by a number of factors. Following recommendations about using semantic HTML and cascading style sheets, as well as separating presentation from content, tends to increase website rankings for well-known search engines. This is because these search engines are no better at reading web pages - and particularly not poorly written ones with lots of Flash - than the average reader.
Applying such technologies and techniques also makes website maintenance easier and means sites are easier to access using a range of different devices, such as PDAs and mobile phones.
"There are 10 million people with disabilities in the UK, six million with dyslexia, untold millions with literacy problems and an ageing population. So there's a huge potential audience that could benefit from making websites more accessible, particularly in today's increasingly competitive online climate," says AbilityNet's Christopherson.
