Consumer broadband bills will be itemised from this summer, offering a breakdown of not only the amount of time spent online but also the amount of bandwidth used in individual web sessions.

As the price war for 512Kbps broadband services escalates, itemised billing will help ISPs cut their losses by enabling them to put bandwidth caps on their sub-£20 products and bill for extra capacity. The bandwidth data will be made available by BT Wholesale from 28 May and will allow ISPs to provide more transparent pricing models for 'turbo' bandwidth services.

To date, they've had no way of proving how much bandwidth a customer had used in a month, making it hard to charge premiums for excessive usage.

BT is planning to offer the service in real time, so that ISPs can warn customers when they're about to exceed their monthly limits. Bandwidth data will be accessible on a per-second basis.