Leading article: Not quite in the bag

We welcome the fact that Tesco, Britain's largest supermarket chain, is encouraging its customers to reduce their consumption of plastic bags. Every little does indeed help. But we must be wary of assuming that this is anything like sufficient action to curb the pollution caused by these ubiquitous menaces to our countryside and wildlife.

What we need is a tax on plastic bags, of the sort introduced in the Republic of Ireland four years ago. This modest levy has cut usage by more than 90 per cent. Tesco's incentive scheme is highly unlikely to produce such dramatic results. Rewarding people for eschewing plastic is one thing, but charging them is the only real way to change their behaviour.

We cannot rely on a supermarket - even one that claims to be ecologically enlightened - to safeguard our environment. What is required is government action.