Monte says he was called in to White Industries at the insistence of its Japanese partners, Mitsubishi Development Company, after a barrister was overheard discussing a point which the directors themselves had only raised the previous night.

Strangely, once bugs are found, Monte says that companies tend to close up and want no further services from the debugging firm. But one of his best and most consistent clients was the late Peter fox of Adelaide Holdings. Monte says that his men found a ceiling bug in Fox's Macquarie Street offices just at the time Fox was moving out of the current round robin tax scheme into film industry tax shelters, and that fox was "absolutely paranoid" about his form of ssecurity. Monte says: "He was paranoid that his competitors and his former staff were listening to him. I was doing his telephones and his offices, and after we found something the first time he had us in regularly to do sweeps once a month or once every two months. He was worried about people who worked for him and then left to start their own tax schemes. He was worried about competitors-and he had a good reason to be."

Our inquiries for this article covered four private inquiry agencies, three major security firms, corporate executives, Telecom, the NSW Corporate Affairs Commission, and senior officers of the Victorian and NSW police. Officials concede that there is cause for concern because debugging devices of varying sophistication are now sold virtually "over the counter" in Australia and elsewhere, however there was a wide divergence of views on the incidence of bugging in Australian businesses. For example, officials could not recall any prosecutions in the past five years, under the federal Telephonic Interception Act or the states' 1969 Listening Devices Acts.