The war of words between Microsoft and the European Commission over the software group's new flagship product has escalated, with Neelie Kroes, EU competition commissioner, denouncing what she calls "aco-ordinated campaign" to discredit the regulator.

Ms Kroes, in a letter to the Financial Times, insists that the Commission is not conducting a "vendetta" against Microsoft. Brussels, she says, is simply trying to ensure that Vista, the operating system set to replace Microsoft Windows next year, complies with EU competition rules.