The relevant regulations are the Personal Protective Equipment at Work Regulations 1992.
Regulation 4 states:
Every employer shall ensure that suitable personal protective equipment is provided to his employees who may be exposed to a risk to their health or safety while at work except where and to the extent that such risk has been adequately controlled by other means which are equally or more effective.
The accompanying guidance states:
Employers should, therefore, provide appropriate personal protective equipment (PPE) and training in its usage to their employees wherever there is a risk to health and safety that cannot be adequately controlled by other means.
In order to provide PPE for their employees, employers must do more than simply have the equipment on the premises. The employees must have the equipment readily available, or at the very least have clear instructions on where they can obtain it.
By virtue of Section 9 of the Health and Safety at Work etc Act 1974, no charge can be made to the worker for the provision of PPE which is used only at work. Section 9 of the Health and Safety at Work etc. Act 1974 states: "No employer shall levy or permit to be levied on any employee of his any charge in respect of anything done or provided in pursuance of any specific requirement of the relevant statutory provisions". Section 9 applies to these Regulations because they impose a 'specific requirement' - i.e. to provide PPE.
Personal protective equipment at work: guidance on regulations, L25, (ISBN 0717604152 - available from HSE Books)