Beyond the daily drill of research, press conferences and interviews, foreign journalists in the mainland are inadvertently mired in a menacing world of intrigue and espionage. But the danger is, for the most part, not directed at them, but rather at the people who co-operate with them as they gather news. The mainland is not the world's greatest fan of media scrutiny, to say the least. The foreign press corps have always had to deal with the likes of none-too-secret agents on their tail, phone taps, bugged offices and local employees who are encouraged to operate as government spies. All that is still in place. But the methods of surveillance have become more sophisticated - if not always more subtle. A European journalist on a recent reporting trip to the central provinces was using her mobile phone to try to track down a local activist. While she was talking, a voice broke into the conversation and scolded her for sticking her nose into local affairs. Another journalist tells of how she interviewed a source in a noisy local restaurant one evening. The next day her mobile rang and she heard the last voice she expected: her own. The call was a recording of her conversation in the restaurant. She has no idea if it was some kind of bounce-back blip in the hi-tech spying game, or whether it was spooks wanting to let her know they were on her case. Either way, it was a jolting reminder of the system's invisible eyes and ears. The latest technology that is pleasing spies and jealous spouses alike is a chip that can secretly turn a mobile phone into a microphone. Security experts say the phone's software is adjusted so that when the phone is called from a certain number, it will answer automatically without ringing, vibrating or lighting up - essentially turning it into a bugging device. All this, and the many other hi-tech eavesdropping and tracking devices now available, can spell danger for the sources who talk to journalists and the Chinese people who work with them. Foreign reporters here are sometimes hassled, impeded from doing their work, forced to sign self-criticisms and, in some cases, threatened or even roughed up. But it is very rare that their lives are endangered or their freedom jeopardised. For Chinese it is a very different matter. On any kind of sensitive issue sources, news assistants, photographers, support staff and the like run a far greater risk of being beaten, imprisoned or worse, for helping foreign reporters. Their attackers are often thugs who have been hired to do the dirty work. This reality places a 'huge burden' on journalists based on the mainland, according to Melinda Liu, Newsweek magazine's Beijing bureau chief and president of the Foreign Correspondents' Club of China. 'It is a very big issue for us,' she said, as before doing any story they must first evaluate who is going to be involved and assess what danger they might be exposed to. 'We have to figure out if it's worth taking the risk,' she said. 'There are some stories we just won't do because we feel it's too dangerous. But if we were to be 100 per cent careful in every case, we would simply not be able to do our jobs.' In many cases, the Chinese involved are prompted to take risks by a desire to get the information out, knowing it would never be published in China. The call could only be made on a 'gut feeling, on a case-by-case basis', Ms Liu said, and no one could predict how situations would develop. 'Sometimes you are going to make the wrong call. It is a huge dilemma.' And if it all means some controversial stories go unreported, it is a dilemma that seems to suit the more opaque elements of the state perfectly well. Peter Goff is a Beijing-based journalist