An advert by BSkyB attacking the broadband speeds of its rivals BT and Virgin Media has been banned by the Advertising Standards Authority.

The press advert claimed: "If you're in a Sky network area, we don't slow your broadband speed down at peak times – unlike Virgin Media and BT."

But the ASA upheld complaints by BT and a member of the public that only "very heavy" users would be affected by slower speeds during peak times.

BSkyB said all BT or Virgin Media customers could potentially be affected by their fair use or traffic management policies.

These meant broadband speeds could be reduced for those who exceeded "fair use" during busy periods, BSkyB claimed. The ASA found that the two companies did have practices in place which resulted in slower speeds for those using popular applications with very large bandwidths during peak hours.

However, the regulator added: "We considered that consumers would infer from the claim, 'If you're in a Sky network area, we don't slow your broadband speed down at peak times – unlike Virgin Media and BT', that BT and Virgin slowed down broadband speeds in peak times for all their customers, including those who used web browsing services with low bandwidths. We concluded that the claim was likely to mislead."

The ASA ruled that the Sky ad breached guidelines on substantiation, truthfulness and comparisons with competitors and said it should not be used again.

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