Tesco is a passionate proponent of a free marketplace in goods and services, a stance this newspaper applauds. Unfortunately, its enthusiasm for openness does not seem to extend to the marketplace of ideas. In Thailand, Tesco is trying to silence critics using tactics that are more familiar to dictatorships than to corporations. A company with pretensions to corporate social responsibility is showing a grotesque lack of proportion in responding to the kind of criticism that in Britain it usually combats with reasoned argument or a resigned shrug - not an aggressive writ.

Tesco Lotus, the Thai operation, claims three critics have damaged its reputation by suggesting that its expansion is unpopular and is crowding out small shops. It is suing one, a gossip columnist who wrote that the company did not “love” Thailand, for £1.6 million. It is suing another, a former MP who told university students that Tesco's expansion plans were “aggressive”, for £16 million. He also faces up to two years in prison if found guilty of “criminal defamation”, a charge that still exists in Thailand despite contravening international human rights law.

Tesco says the right to free speech does not imply the right to defame it. But its use of this archaic law, and its pursuit of massive damages, is extreme. A victory with nominal damages would surely suffice to restore its reputation. Corporate HQ has either lost control of the Thai operation, or is off its trolley. To pursue these charges will be to court worldwide opprobrium. The Lotus is a symbol of enlightenment. Tesco Lotus needs to start living up to its branding, and its British masters must tell it to.