This shooting down of a supposed "green fuel" repeated his feat when he was the first UK scientist to show, loud and clear and by evidence- based argument, that diesel fuel, by its residue of fine particles, causes more problems than it solves. As he sardonically said to MPs: "the switch to diesel which is now taking place may well be a large-scale experiment in lung cancer".
Simon Wolff combined, as few do, campaigning zeal and campaigning success with true academic integrity. Of course the oil lobby were unhappy with his torpedoing of two of their carefully advertised "green fuels". But this did not make him yet another Identikit Green bore: rather he was distinct from most Greens in not falling for technical fixes such as unleaded fuels and catalysers when what was needed was to stop building new roads.
His work at the Medical School of University College London, where he worked first as Lecturer, then Senior Lecturer in Toxicology, from 1986, centred round the degenerative effect of free radicals and oxidants generally in the context of diabetes and ageing. His work was internationally recognised: he had over a hundred papers, and publications in Nature magazine and elsewhere, and contributed to many international conferences. The outcome of his work could be drugs to reduce the danger for diabetics of cataract or even ways to slow the ageing process.
Simon Wolff was active in public from the time when in 1973, as a schoolboy (at Rugby School), he helped rescue Harold Wilson from drowning while he was boating off the Isles of Scilly where Wilson had a cottage. When Lindis Hallan (whom he married in 1988) and he moved to Archway Road, in Highgate, north London, in the late Eighties they found a battle under way against the Department of Transport's planned Archway motorway. A determined campaign had beaten off the department through four public inquiries: now officialdom branched out into a planned all-London network of new roads.
Wolff's thinking was, as always, unusual in being direct and simple: if more traffic means more pollution, why build more roads? Apparently a simple thought, but one shied away from by political parties and professional environmentalists. Wolff absorbed the Archway spirit: intellect and fighting on the barricades. You need something to say - but you also need courage to say it whether or not officialdom deems it the right time and place. In 1990, a battered Cecil Parkinson, then Minister for Transport, conceded defeat: for the first time in a quarter of a century Archway was safe and it was Wolff who helped make it so.
Scientists have dogmas as much as politicians or priests, but Wolff never minded a clear-eyed look. He distrusted Pavlovian reactions to radioactivity and when it was reported that areas with more radon (a radioactive gas) have higher cancer levels (with the inference that the level of cancer was connected to the level of radon), he showed that these areas were usually economically better off. More car-driving with increased ingestion of benzene, not radon, he argued, would have increased cancer levels. Again, he suspected that laying all ills at the door of tobacco was a move to exculpate worse pollutants, notably transport fumes, and would say, "I'll stop smoking if you stop driving."
Simon Paul Wolff, toxicologist and campaigner: born Harborough Magna, Warwickshire 3 March 1957; post-doctoral research fellow, Brunel University, London 1984-86; Visiting Assistant Professor, Department of Ophthalmology, Columbia University, New York 1984-86; Lecturer, then Senior Lecturer in Toxicology, University College Medical School, London, 1986-95; married 1988 Lindis Hallan (one son, one daughter); died London 25 November 1995.