The court needs to send a clear message that corruption, especially by those holding high public office, will not be tolerated, said District Judge Hamidah Ibrahim at the sentencing hearing of Peter Lim Sin Pang on Thursday.
"With every public servant's fall from grace, the confidence in the public service is affected and that is a fact which I could not ignore," said the judge.
"Every misdemeanour that a public servant commits... has an effect of lowering in the eyes of the public, the standing of the institution he serves and unfairly casts a negative light on the public service as a whole."
In sentencing Lim to six months jail, District Judge Hamidah Ibrahim said a fine in this case "would not be appropriate as it would trivialise the severity of corruption".
Lim, who last held the rank of Singapore Civil Defence Force (SCDF) commissioner, is appealing against the sentence.
The 53-year-old was convicted of one count of corruption for his sexual encounter with Ms Angie Pang Chor Mui, 49, in exchange of furthering the business interests of her then-employer Nimrod Engineering.
At a hearing last Friday, Lim admitted to seven other trysts with two other women - Ms Esther Goh Tok Mui and Ms Kelly Lee Wei Hoon, both in their 40s. They were working for information technology firm NCS and technology company Singapore Radiation Centre respectively, both of which were vendors of the SCDF.
In total, Lim faced ten charges of corruption, two of which were stood down and seven others taken into considered during his sentencing.
The prosecution had pressed for a jail term of five months, similar to the sentence given to former law professor Tey Tsun Hang on June 3, in the closely watched sex-for-grades trial.
But defence lawyer Hamidul Haq had argued in mitigation that Lim should not be jailed and should instead be given a "hefty fine" because, among other things, the SCDF had not suffered any losses since Lim's actions did not lead to the tender being awarded to Nimrod, and SCDF's procurement system had therefore not been compromised.
Lim could have been jailed for up to five years and a fine of $100,000 for each charge.
His sentencing comes two days after the Attorney-General's Chambers decided not to appeal against the Feb 14 acquittal of former anti-narcotics chief Ng Boon Gay, who had also faced corruption charges earlier.