Workers with dyslexia are "suffering in silence", causing them unnecessary stress and affecting their performance, a new report claimed today.

The TUC said the condition affects up to 2.9 million workers, although some may not be aware they have a problem.

The organisation published a new report aimed at helping firms tackle the difficulties caused by dyslexia, such as finding it difficult to follow written instructions, deal with maps and charts or write reports.

Managers were urged not to ignore any difficulties encountered by workers with dyslexia but to think of ways to help.

TUC general secretary Brendan Barber said: "Almost three million workers suffer from dyslexia and many may be suffering in silence or unaware of their problem.

"The Disability Discrimination Act has gone some way towards breaking down certain taboos around disability at work and has helped many workers get the help and support they need.

"However, many others have perfected the art of masking their problems, which can cause them unnecessary stress and lead to poor productivity."

The TUC said it knew of cases where workers with high IQs had been criticised or even disciplined because of errors caused by dyslexia.