If your microphone squeaks, squeals and screams at you, make one joke about it and carry on. If the electronic noise persists switch off the microphone and make do without. Recently I spoke to the Southend Law Society and hardly had begun my address when the amplifiers began broadcasting not only my speech, but also messages being transmitted by the local police. The first time this happened, the audience roared its enthusiastic approval, but after a short while the interference became an irritating distraction. Temperamental microphones and talkative public address systems are good for one long laugh, but the novelty rapidly wears off.