TWO civil servants involved in intelligence work are suing the Government for underpayment of salary amounting to around $1.5 million, the High Court heard yesterday. The widow of Mr George Lau, who died aged 42 last October, and Mr Hugh Ollerenshaw, 57, are asking Mr Justice Jones for a declaration that they are entitled to the back pay which also affects their pensions. If the plaintiffs succeed, Mr Lau's widow, who is unwell and has three small children, stands to get more than $1 million, while Mr Ollerenshaw, who has been in government service for 35 years and received commendations and awards, would get about $500,000, Mr Gerard McCoy said. He said Mr Lau was told, when he accepted the sensitive job as an assistant police research officer within the police force, that the pay was equal to a chief inspector's. When interviewed, Mr Ollerenshaw was also assured that there would be parity. The problem arose in 1989 when police were put on a separate pay scale and given a 12.5 per cent pay rise. In June 1991, 36 intelligence officers were awarded $28 million after the Government settled the case in court. However, Mr Lau and Mr Ollerenshaw were in a different position as they joined after the new police scale was introduced and the Government refused to settle. Mr McCoy told the court that Mr Ollerenshaw applied for the job in January 1989. Just 10 days later, the police got their pay rise, backdated to April 1988. Mr McCoy said it was therefore difficult to work out when, if ever, parity between the two posts was severed. Counsel argued the distinction between the 36 serving officers and the two plaintiffs was one without a difference. He said the pay rise was insignificant in law - what was significant was Exco's decision to implement it, which was made in January 1991 and until which the Government could not lawfully vary or alter the terms and conditions of service. After that, the Government could employ civilians on disparate terms. Mr McCoy said for 20 years the civilian research officers had parity with chief inspectors and, on promotion, with superintendents. Mr Lau had been working as acting assistant police research officer from March 1987; he was confirmed in July 1989 and worked there until his death. Final submissions are to be made to Mr Justice Jones by Mr McCoy and Mr David Fitzpatrick, for the Government, on April 14.