(b)  It is a competitive process. Design changes are generally not shared between manufacturers, given the confidential and commercially sensitive nature of such information;

(c)  The success of any design development is dependent upon a variety of factors, of which certain key factors are beyond the control of the tobacco manufacturer. For example, a manufacturer may want to use a cigarette paper of a particular porosity and composition to wrap a tobacco rod. Theoretical work leads to the conclusion that this paper may create the recipe required for the right "smoke", in conjunction with the other constituents of the cigarette. The manufacturer has to obtain the cigarette paper which meets his requirements, usually from an independent paper manufacturer. This process, in itself, involves liaison over time and experimentation. Even supposing that the required paper specifications can be supplied, the development of the cigarette founders unless the paper can be successfully accommodated within the cigarette making machine—built and supplied by the machine manufacturer, who is continually developing newer and faster machines. Such machinery undergoes a continuous evolution to improve its performance; and

(d)  This process cannot even begin unless the tobacco manufacturer can source suitable materials in sufficient quantities and of the right quality from third parties.

—  the actual tobacco blend used by the manufacturer in the tobacco rod, which additionally may include a combination of crushed rolled stems of the tobacco leaf and tobacco sheet;

—  moisture content;

—  the density of the tobaccos, and hence the weight of the tobacco present in the tobacco rod, which also affects the draw resistance of the tobacco rod (see paragraph 7.10);

—  the length of the cigarette;

—  the circumference of the cigarette;

—  the length, composition and specification of the filter (if any);

—  the degree of filter ventilation (if any);

—  the degree of porosity and the combustion characteristics of the cigarette paper; and

—  how the cigarette is smoked.

  7.8  The inter-relationships of the above factors also demonstrate the complexities involved in the design of cigarettes and the range of issues that need to be considered when seeking to make modifications to reduce the tar yields of products, whilst at the same time producing a cigarette that is acceptable to the smoker.

  7.9  During puffing, the smoker will draw mainstream smoke into his or her mouth. This smoke will be visible, due to the presence of particulate matter and will also include a gaseous component (vapour phase). Under laboratory smoking conditions, the particulate matter in the whole fresh smoke, when collected on a Cambridge Filter pad, provides the basis of the "tar yield" and "nicotine yield" figures that are printed on UK cigarette packets (see paragraph 4.51).

  7.10  Some commonly used terms relating to cigarette combustion are defined as:

(a)  "Whole fresh smoke" or "mainstream smoke"—the freshly generated whole smoke delivered from the burning cigarette to the mouth of the smoker;

(b)  "Condensate"—the particulate matter of whole fresh smoke which is left after (varying degrees of) evaporation of some components. This condensate will contain nicotine. It is collected under laboratory conditions using a variety of devices;

(c)  "Tar"—the generic term for particulate matter in mainstream smoke;

(d)  "Tar yield"—can be defined in various ways but typically refers to the amount of tar, by weight, exiting from the unlit end of a burning cigarette. Among other things, the tar yield of any individual cigarette will directly depend upon the number of puffs taken from the cigarette, the volume and duration of each puff and the flow rate at which each puff is drawn from the cigarette; and

(e)  "Draw resistance"—the measure of effort required from a smoker to draw mainstream smoke through a tobacco rod and/or a filter tip.