Possible Clues:

• Ideal insurance for Liberal Democrats
• Sort of policy that threatens both government and opposition?
• The sort of 2 down that might provide more than a second of entertinment
• Bystander perhaps playing vital part in crowd scene?
• Seems you're assured of there being a couple of entertainments before this one
• Another (uninvolved) person
• Someone other than the principals
• *Lively social event
• Mad Hatter's social event
• Type of insurance got by number crossing road per annum