How do you sue ghosts? For lawyers like John Messham, it's an all-too-familiar riddle that has to be solved. Take for example the tragic case of a London couple, who moved to Cornwall to begin a new life. Within a year, the husband was diagnosed with mesothelioma, an invariably terminal lung cancer caused by inhaling asbestos.

His employers, an east London laundry, were responsible for exposing him to the asbestos when he worked on steam pipes. But what became of the employers? The company had gone bust years before and there seemed no possibility that they or their insurers could be traced. "The company had gone," John said. "And there were no assets."

But John's dogged detective work eventually found the insurance company and he lodged a successful claim.

Few lawyers have more expert knowledge than John of the ravages of asbestos-related injury. "It is a scandal - many people continued to be exposed to asbestos long after its perils became known.

"Acting for the victims makes special demands on solicitors," John said. "You have to work quickly because they often have only a short time remaining before they die, and yet you often need to make wide-ranging inquiries."