Insurance is there to protect your arse should anything/everything go wrong. It can cover you for public liability (being sued by injured jugglers), employer's liability (being sued by injured volunteers), and potentially also for equipment loss/damage (vandals torching £20k worth of big top in the night?) and cancellation due to bad weather.
It is a legal obligation to carry employer's liability insurance if you have anyone working for you. This is unlikely to include performers (who are contractors, and who should have their own insurance) . Advice varies about whether this does or does not include unpaid volunteers . In any case, volunteers may not be covered by public liability insurance.
Insurance companies often have a list of "dangerous activities" which are excluded from the policy. Unfortunately, most event insurance companies think "circus acts" constitute "dangerous activities". Even when they cover circus activities, it's difficult to get cover for (e.g.) fire juggling - BJC 2006 and 2008 had no insurance for any fire juggling anywhere. Make sure you have read the policy and you understand any exclusions.
Insurance may cover some kinds of losses that may happen in advance of the event (e.g. the venue going bankrupt with your deposit money), in which case it can be an advantage to buy the insurance early on to make sure you are covered.
BJC 2009 and 2013 used : Graham Sykes http://graham-sykes.co.uk/
BJC 2010 used:
The Event Insurance Team
Event Insurance Services Ltd
20a Headlands Business Park Ringwood Hampshire BH24 3PB
Tel: 01425 470360, Fax: 01425 474905 Email: firstname.lastname@example.org
2010 Insurance Certificate. File:Elcert.pdf
2010 Insurance schedule. File:Schedule.pdf
BJC2007 used First Act Insurance.
BJC2001 was sponsored by Dixon Chalmers Insurance.
BJC2k arranged a contra-deal with Torribles Insurance - they provided £2million public liability insurance and BJC2k agreed to promote them as the event insurers and let them send literature to the event for the info desk.
Torribles no longer cover circus events.
Manchester, Durham and Bristol BJC also used John Torribles