Yes - in almost all cases. If you employ persons before, during or after an event you will probably need Employers Liability Insurance. Please refer to the Health and Safety Executive for further information.
It is also responsible practice to take out Public Liability Insurance with a minimum £5 million Limit of Indemnity and with an Indemnity to Principal clause. Events that cannot demonstrate that they have appropriate insurance will not receive the support of the Council or other members of an Event Safety Advisory Group.
All contractors, performers and leisure attractions will also need their own Public Liability Insurance with a minimum £5 million Limit of Indemnity. It is recommended that the event organisers obtain copies of the insurance as part of the tender process.