The Health and Safety (First-Aid) Regulations 1981 require employers to provide adequate and appropriate equipment, facilities and personnel to ensure their employees receive immediate attention if they are injured or taken ill at work. These Regulations apply to all workplaces including those with less than five employees and to the self-employed.
What is ‘adequate and appropriate’ will depend on the circumstances in the workplace. This includes whether trained first-aiders are needed, what should be included in a first-aid box and if a first-aid room is required. Employers should carry out an assessment of first-aid needs to determine what to provide.
The Regulations do not place a legal duty on employers to make first-aid provision for non-employees such as the public or children in schools. However, HSE strongly recommends that non-employees are included in an assessment of first-aid needs and that provision is made for them.
http://www.hse.gov.uk/firstaid/legislation.htm