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Middleton believes that a by-product of coaches being more diligent with tackle technique is that the game becomes more entertaining to watch because of fewer stoppages to review high tackles.

Other ingredients sometimes used are the poisonous metal, mercury, and kojic acid - a by-product from the manufacture of the Japanese alcoholic drink, sake.

In the rural tranquillity of central Ukraine, this man-made canyon is the by-product of 61 years of mining.

Food waste is sent to an anaerobic digestion plant, and converted into energy by burning the methane waste that comes from it, with the by-product being used for farm fertiliser.

Slot's team are also attempting fewer shots in each match, down to 15.2 from 20.6 last season, which is perhaps another by-product of introducing a bit more control and conservatism into the system.