Sitting in the glass-fronted private dining room that overlooks the Thames, Paul Adams, the no-nonsense chief executive of British American Tobacco, pulls out a cigarette from a pack of Kool menthol and asks: “Do you know what the magic in this is?”

The product, called Kool Boost, features a small capsule that, when the filter is squeezed, releases an extra boost of menthol flavour.