A cleaning supervisor who took an upskirt video of a woman after she fell asleep next to him on a bus was jailed for three weeks yesterday.

Subramaniyam Supan, 54, pleaded guilty to one of two counts of intruding into the privacy of the 25-year-old woman by using his mobile phone to take a 20-second clip of her on the No. 7 service in Clementi Avenue 5 on May 16.

The court heard that the woman boarded the bus at about 7.20pm and sat next to Subramaniyam on the upper deck.

Shortly after, she dozed off.

Another passenger was about to alight when she saw Subramaniyam placing his mobile phone between the victim's legs.

The witness told the bus driver, who immediately stopped the vehicle and asked passengers to alight before he called the police.

The victim realised what Subramaniyam had done only when she was informed by the witness and the bus driver.

Deputy Public Prosecutor Star Chen sought a jail sentence of two to four weeks.

Pleading for a fine, Subramaniyam said he was his family's sole breadwinner and regretted committing the offences.

District Judge Low Wee Ping said a jail sentence was warranted to deter other people from doing the same thing.

"The mobile phone has been invented to be used for good purpose. Nowadays, it is being used as an instrument of crime,'' he said.

The maximum penalty for insulting the modesty of a woman is one year's jail and a fine.