His work was presented to the two-day conference Journées de la Recherche Porcine in Paris earlier this year.

The process is an essential first step in optimising the downstream processing of pig meat, since the workings of the inter-related circuits for each of the primals (loin, ham, belly and shoulder) can be quite opaque at times.

The problem arises from trying to track widely differing cuts that are subject to different degrees of transformation.

At the outset, Mr Legendre establishes a baseline conversion factor from carcase to primal of 0.86, based on a class E charcuterie half carcass weighing 44.6kg.

The study acknowledges that the trade in pig meat is pan-European, so while trade flows are tracked up to the French border, the study does not attempt to delve into other national industry classifications or trade circuits.

The primary players that Mr Legendre identifies are: abattoirs with cutting halls; specialist cutting and boning businesses; fresh meat wholesalers; industrial scale processors and manufacturers; wholesalers of finished products; craft butchers and charcutiers; multiple retailers; cash and carry operators and food service.

Multiple retailers directly control just one per cent of French cutting and boning, the most visible being Intermarché. In manufacturing, this proportion rises to 12 per cent, double the volumes handled by charcutiers and three times the volumes processed directly by food-service operators.

At retail level, Mr Legendre found, multiple retailers handle 69 per cent of the pig meat tonnage sold in France, 12 per cent is sold through charcutiers and 19 per cent in food service.

Mr Legendre flags up the fact that it was not possible to track offals, an important throughput for certain areas of charcuterie.

For an online summary of Vincent Legendre's paper Cartographie des flux de viandes de porc de la sortie des abattoirs a la mise a disposition aupres du conommateur final, click here.