FOR a struggling author looking for the big break, the advertisement in the latest issue of the Australian Society of Authors newsletter must have looked like a godsend. ''Looking for a writer/publisher,'' it began, ''for the story of [sic] Superintendent of Police who had his life destroyed after exposing corruption. The longest-running High Court case in British history and so far costing over $300 million from the public purse.'' Who is this downtrodden former defender of public order now enmeshed in a case whose costs alone make the total for the Lorrain Osman case look like small change? None other than our old friend Yaqub Khan, the former Royal Hong Kong Auxiliary Police Force officer sacked in 1978, amid allegations he made irregular pay claims and investigated a triad society without authorisation. Khan fought an 11-year legal battle against wrongful dismissal that culminated in a 1990 legal victory, including a $500,000 back pay award. With legal costs and other deductions that figure was whittled down to a mere $30,000, and a year later the Privy Council rejected his leave for a special appeal, thereby closing off his final channel of legal redress. There are many who will say Khan was unfairly set up for a big fall, but that his relentless refusal to let the matter rest has lost him sympathy. This newspaper is among several media organisations an embittered Khan faxes regularly giving him a chance to offer pungent opinions on Government officials, with the Chief Secretary, Sir David Ford, a favourite target for abuse.