I think what you are referring to is Industrial Injuries Disablement benefit.
To qualify for this you have to have an injury or illness as a result of your employment.
Then as a result of this injury/illness you would have to suffer a permanent disability. The amount of disability is then assessed by a doctor and you receive the appropriate amount of benefit. No benefit is payable if the amount of disability is assessed at less than 14%.
No benefit is paid merely because of an accident at work you must meet the criteria above.
See this article by the DWP
http://www.direct.gov.uk/en/DisabledPeople/Fin ancialSupport/OtherBenefitsAndSupport/DG_10020 628