A polio victim enjoyed a successful 14-year civil service career on the strength of a forged exam certificate, a court heard yesterday. Cheng Koon-wai used the fake document because he felt inferior due to his limp. His bosses in four government departments, including the police, failed to see the certificate attached to his job applications was a fake. The deception was eventually uncovered in March this year during a check on staff qualifications, Western Court was told. Cheng, 41, saw his career end in disgrace when he was given a three-month prison sentence, suspended for a year, and fined $15,000. He admitted three charges of obtaining an advantage by deception. Cheng, married with two young children, started out as a clerical assistant with the Government Secretariat in 1982. After three years he was transferred to the Agriculture and Fisheries Department, where he worked as a field assistant. In 1990 he applied for and secured a job as a clerk with the police force. He was switched to the Water Supplies Department as a communication control officer in 1994. Magistrate Ian Candy was told Cheng had forged a Hong Kong Certificate of Education Examination, dated 1972, which showed him to have passed six subjects. In fact, he had failed most of his exams. He was found out when an internal check was carried out on the qualifications of all Water Supplies Department staff. Cheng was arrested by the police in June. His lawyer, Duncan Lai Wing-fai, told the court that Cheng was driven to commit the offence because he felt inferior due to his physical disability after suffering from polio. Mr Lai said Cheng forged the certificate to have a better chance of getting the jobs which in fact only required applicants with Form Four standard. The lawyer urged the court to consider the defendant's contribution to society as he had been a voluntary youth worker during the 1970s. Mr Candy said it was a 'natural consequence' that Cheng should lose his job as well as his pension. He said the offence was serious and would normally warrant an immediate custodial sentence, but he took into account Cheng's guilty plea and his sense of remorse.