As bad ideas go, this one is a corker. Michel Barnier, French agriculture minister, wants to consolidate the European Union’s self-sufficiency in food and encourage regional groups of developing countries to do the same. It is entirely the wrong lesson to draw from the global food crisis.

The claim of Nicolas Sarkozy’s government to be in favour of agricultural reform is almost completely specious. Paris says it wants to reduce agricultural subsidies, at least those paid at an EU-wide level. This, no doubt, is connected with the fact that the accession of poorer, more agrarian countries to the EU is jostling French farmers as they wallow in their privileged position sucking at the Brussels teat.

But it also wants “community preference” – code for maintaining Europe’s absurdly high agricultural tariffs or raising them yet further. (One consolation: if the Doha round of trade talks fails, we will at least know where to place the blame.)

Despite the public attention on cash subsidies from Brussels, at least as much money has traditionally been transferred from EU consumers to farmers through import tariffs, which raise domestic food prices. The French policy would maintain or worsen this.

The global food crisis should actually be a good opportunity to reform agriculture by lifting farmers off subsidy and tariff protection and getting global markets to work better. But though some emergency policies are going in the right direction – developing countries cutting food tariffs and the EU dropping its “set-aside” policy of paying farmers not to grow food – many of the longer-term policy responses being mooted would make things worse.

Raising tariff walls yet higher is one such. Trade barriers provide a disincentive to developing countries to invest in agricultural production and export capability by removing a potential customer. Access to international markets raises incomes, often by several hundreds of per cent, for poor farmers. Cutting off that source of income reveals the emptiness of France’s conception of itself as a country that truly cares about the developing world.

Food autarky is not food security. For Africa, beset by highly variable harvests and unproductive, largely rain-fed agriculture, attempting self-sufficiency today is a recipe for regular famine. Improving farm productivity, and the ability of growers to get their produce to market, is an imperative. Snatching away export markets that could reward such improvements is utterly perverse.

This is not just a bad idea. It is a potentially lethal one. It should be discarded.