Day One of the corruption trial of former Singapore Civil Defence Force (SCDF) chief Peter Lim Sin Pang concluded on Monday evening without the star prosecution witness taking the stand.

Ms Pang Chor Mui, general manager of Nimrod Engineering, and the woman at the center of the case, did not take the stand as expected. This was due to a last minute change in the order of the witnesses.

The prosecution said they decided to call other witnesses first to establish the facts surrounding the charge, resulting in the change of the order of witnesses.

Nimrod's business development manager, Mr Raymond Tan Peng Leng, was the first to take to the witness stand, during which the court sought to establish whether his company knew about the tender details of radiation portal monitors that the SCDF was procuring before it was made public.

Both prosecution and defence lawyers spent a substantial amount of time on a series of emails between Nimrod and its potential suppliers and the chronology of the tender process.

A second witness, sales manager Mr Lee Yong Chin, also took the witness stand on Monday. He was asked how the company sourced for business.

It was also revealed that the tender for the radiation monitors was submitted an hour before it closed May 3, 2011. Subsequently the tender was cancelled and a second tender was put up in December. No reason was provided on this.

Lim, 52, faces 10 counts of corruption in the sex-for-contracts case. But, as decided earlier, the prosecution will stand down on the other nine and proceed with one charge involving Ms Pang Chor Mui from Nimrod Engineering first.

Lim is alleged to have received oral sex from Ms Pang on May 2, 2010 in exchange for furthering the business interests of her former company.