BACK facing the camera, the couple began indulging in a distinctly X-rated moment.

Scene from an Internet voyeur site, or a cheap **** film? No, the above scene took place recently on a public bus in Singapore in broad daylight.

The couple's indecent romp was caught on video by a fellow commuter, who sent the mobile phone footage to Stomp, The Straits Times' interactive portal for readers. Because of its offensive and objectionable content, the clip was not posted online.

The film does, however, raise questions about public decency and the pervasiveness of new media. Who, in fact, stepped furthest over the line of acceptability: the couple for taking their midday rendezvous too far, or the commuter who decided to record it on video and spread it over the Internet? All things considered, who deserves more flak?

Asked by The Sunday Times, members of the public had mixed reactions.

Banking executive S.R. Lau, 24, was more disapproving of the couple.

'They are making a nuisance of themselves in a public place so I have no sympathy for them. If there is a 'free show', I don't fault the person for taking the video.'

Personal assistant I. Tan, who is in her early 40s, said: 'I'm more critical of the couple because they should not do this in plain sight of everyone. It is even more unacceptable because it is done in the bus.'

Others, however, offered a different interpretation.

Said undergraduate Chiu Mei Ji, 22: 'Honestly, they should just get a room. But I do give some of them the benefit of the doubt that they just can't control themselves.'

Others thought the decision to record this sexual escapade was as odd as the escapade itself.

Mr Raymond Ng, 43, said: 'If there is a suspicious package, would you tell the bus driver or would you just videotape the package?'

Added medical student Jason Tan, 24: 'I would have reported the matter to the driver. If you tape an indecent act, it's like you're capturing **** and you're just being a busybody.'

But invasion of privacy can be justified if it serves a larger public interest, said Professor Mark Cenite, assistant chair of the Wee Kim Wee School of Communication and Information at Nanyang Technological University.

He said: 'Images of Saddam Hussein's execution, intrusive as they are, can serve the larger purpose of verifying that the execution took place and the manner in which it happened, and can raise larger issues about capital punishment.'

So what was the intention behind recording the incident?

Some feel this footage might have been taken to shame the couple. Others suggested the whole scenario was an exhibitionist stunt set up by the couple and whoever filmed them.

Psychologist Danny Ng said the man who recorded the incident was unlikely to be a serial voyeur, because he did not go out of his way to secretly tape the scene.

Said Dr Ng: 'This couple made it obvious enough for him to film the act.

'Frankly, I think that the couple should have practised more self-control and restraint. But one cannot entirely blame the onlooker as most people are naturally curious about unusual happenings and would want to watch if they are given a free show.'