Until then, many believed such methods were employed only in films or in the tough US business arena.

But now, according to Mr. Frank Monte, prominent Sydney private investigator and managing director of Monte Corporate Security, the practice is widespread.

"We no longer pretend that bugging does not exist," Mr. Monte said.

"It has become like CB radio was a few years ago.

"No-one wants to admit doing it, but most are."

Mr. Monte said there was a tremendous demand for bugging equipment, and although he sold it he would not plant the devices for a client.

"There's not enough in it for us and it's illegal," he said.

"Legally you can buy a bug but you cannot put it on."

With the emergence of bugging, a growth area for security companies had been debugging premises.

The prominence given to the White Industries bugging made people aware of the need for companies to be secure from electronic surveillance.

But according to Mr. Monte, who lists industrial and commercial work as about 50 per cent of his business, bugs are merely accessories to gathering intelligence for a client.

"Bugs can give you good information but you can't rely on it," he said.

"They are useful, but if you rely on them and nothing else it's not much good. "A decision made in a bugged room may be later changed elsewhere or those in the room could quite easily be lying about their plans."

Mr. Monte said that, in the industrial sense, people wanted strategies of their opposition and the only reliable way to get it was to infiltrate the premises.

"On television, you always see the agent copying plans, but in real life this is very rare," he said.

"People are more interested in how the opposition is doing it's business.

"You find this sort of thing out by following a rep and seeing where he stops and the volume of business he does at each stop.

"You don't need a bug. A good man needs only a pen and pad to get the information.

"All the gizmos in the world are secondary."