It is usual for events to require a Premises Licence for the period of the event involved under the Licensing Act 2003. However for smaller events (less than 500 people) of short duration (less than 168 hours) organisers may not require a Premises Licence but may give the Licensing Authority a Temporary Event Notice (TEN).
If your proposed event involves one or more of the following activities then you are likely to need to obtain a licence (or temporary event notice).