From rationed sunflower oil in Spanish supermarkets to pricier sushi in Japan, the war in Ukraine is rippling across global dining tables. Russia and Ukraine exports account for 12 per cent of total calories traded in the world, according to the International Food Policy Research Institute. North Africa and the Middle East rely on these countries for half their cereal.

The immediate consequence is higher food bills. Producers such as Nestlé, Mondelez and Danone — which just this week reset margins lower — were already dealing with inflated input costs. Unilever, prewar, reckoned these would add €3.6bn to its €23bn bill. Some are preparing the ground for a rare fourth session of negotiations with retailers: tough price-setting talks that, in normal years, are completed in a couple of rounds.

That assumes they can procure goods in the first place. Anecdotally, some small flour mills and other processors, finding themselves unable to replenish depleted inventories, began triggering force majeure Clauses this week. More could follow. Nor is it just exported goods. About a quarter of Europe’s supply of key nutrients such as nitrogen and phosphate used in fertilisers comes from Russia, Belarus and Ukraine. That stands to have an impact on future domestic European crops too.

Longer term, disruptions to supply could trigger a rewriting of agricultural rules. As with energy, there will be renewed efforts in substitution and procurement — likely meaning more focus on self-sufficiency. The UK produces about 60 per cent of domestic food consumption by economic value, part of which is exported.

As with gas, some of these efforts dovetail with existing policy campaigns, such as a move towards more organic farming. But others are contradictory. European policy moves towards greening, such as dedicating a portion of arable land to non-productive elements, may be unwound if the focus reverts to self-sufficiency.

Bigger risks are in store for emerging markets, where food is a bigger component of spending and — in cases such as Egypt or Indonesia — reliance on Russia and Ukraine is greater. History shows there are few more potent sparks for social uprisings than empty tables.