Procter & Gamble yesterday threw its weight behind growing environmental efforts to reduce excess packaging, with plans to switch its entire $4bn (€2.94bn) North American liquid detergent output to smaller bottles of double concentrate.

The move comes as Wal-Mart, P&G's largest customer, is pushing its suppliers to cut packaging by at least 5 per cent. In Europe, Tesco and other big supermarket chains have also said they want to cut the amount of packaging.