Mesothelioma is a killer, 3000 deaths a year in UK. Mesothelioma has the quality of a silent killer, as it manifests itself at a very late stage, usually when it is too late. The cause, or one of the causes, appears to be the inhalation of asbestos dust. This dust may be found in the atmosphere generally, and in the workplace, depending upon the construction of the building and the nature of the activities carried on there. The process towards malignancy, cancer of the pleura, can take many years, almost a lifetime in some cases. Medical and scientific experts believe that the dust leads to a change in the cells, and inhibits the naturally resistant cells. In the normal run of court cases, the claimant seeks to prove negligence on the part of the employer or other defendant, that he has suffered injury or damage, and that that injury or damage was caused by the negligence. The claimant must prove his case on the balance of probabilities. Mesothelioma presents a big problem. The claimant, victim, employee, patient, deceased, whoever, can prove the presence of asbestos and the negligence of the defendant. But proving cause and effect presents a real stumbling block. Over the years, often many years, the claimant has been employed by a succession of employers, some of whom exposed him to asbestos, some of whom were negligent, some of whom employed him for a long period and some for a short period. Asbestos was very widely used in a multiplicity of ways in the 1960s and 1970s, and the consequences have lingered on. Even if the presence of asbestos can be proved, it may not necessarily have been the cause of the mesothelioma. Therefore, the judges created a special rule for such cases, namely that if the claimant could prove negligent exposure to asbestos by the employer the claimant is entitled to damages, each and every employer being liable for the entire amount of the damages. Each of these employers increased the risk of mesothelioma, so all must bear the responsibility. The three House of Lords and Supreme Court cases are Fairfield v Glenhaven Funeral Services [2002] UKHL 22, [2003] 1 AC 32; Sienkiewicz v Greif UK [2011] UKSC 10, [2011] 2 AC 229; and Durham v BAI (Run Off) [2012] UKSC 14, [2012] 1 WLR 867, paras 3–6. This leaves the employer seeking to escape liability by having to prove that there was no asbestos or that he took all reasonable steps to protect the employee. For example, he was aware of the possible problem, he took professional advice, he carefully removed all asbestos, or he sealed off any asbestos, he installed a safe system of work, everybody was trained and warned about the possible risk, protective clothing was provided, all safety measures were supervised and enforced, and so on. The defendant may be able to set up a successful defence. The asbestos mesothelioma claim will not necessarily inevitably succeed. In 1974, the claimant, now deceased, carried out scientific experiments in an underground laboratory when a university student as part of his studies. The laboratory contained central heating pipes lagged with asbestos. Many years later, the deceased died of mesothelioma caused by asbestos dust. The university successfully argued that having regard to the state of knowledge in 1974, they did not and could not have reasonably foreseen the risk and there was no evidence to show that they had accordingly negligently increased the risk (Williams v University of Birmingham [2011] EWCA Civ 1242).