Bring-a-picket party

Picture this: The offices of the British Roads Federation are surrounded by chanting roads demonstrators. Two are on the roof, hoisting a banner. The thin blue line of the police guard is wavering. Suddenly the phone rings.

'Is that the BRF,' asks a woman.

'Yes,' answers the receptionist.

'Is there a demonstration going on outside?' she asks.

'...Er, yes,' replies the receptionist.

'Oh good. I'm supposed to be on it. But I've lost your address. Can you tell me where you are. Oh, and could you tell them I'll be along shortly.'