In addition to the common law, there is also criminal (or statute) law. This is the written law of the land, consisting of Acts of Parliament or Rules, Regulations or Orders made under them. Criminal liability can arise for failing to comply with the requirements of these, leading to prosecution, fines and, in extreme circumstances, custodial sentences.
The main statutory legislation is the Health and Safety at Work etc. Act 1974, supplemented by more specific regulations made under it. The Act applies to any organisation which has at least one employee. It requires employers to protect their employees and volunteers if they have them. In these circumstances, you should generally afford the same level of protection to volunteers as you do to any employees. For example, this may mean that you have to provide them with relevant information, training or personal protective equipment.
It is also important to note that certain aspects of the Act may still apply to you even if you do not have employees. In particular, this would be where you control non-domestic premises used as a place of work or where you provide machinery, equipment, appliances or substances for use there by others (e.g. volunteers, members of the public). Here, you must take reasonable steps to make sure that these are safe. For example, if you were providing a ladder for use by volunteers you would need to make sure it is free from any defects.
You may also have other, more specific, legal responsibilities too. Examples include, the need to complete a fire risk assessment, manage asbestos or where you have construction work completed at your premises.