Three BT television commercials have been banned for making misleading claims about broadband speeds.
Sky UK complained to the Advertising Standards Authority (ASA) because BT claimed that its BT Infinity products "offers faster download speeds than Sky".
The company argued that this was misleading and challenged whether this claim could be substantiated.
A member of the public also registered an objection, as they had used both Virgin Media and BT Infinity and found no difference in their user experience.
The complainant therefore said the claims stating BT Infinity has more responsive online gaming and smoother video calling than Virgin Media are misleading.
The ASA has upheld the complaints and told BT not to show these advertisements again.
In its ruling, the watchdog argued that the claims made in the ads "had not been adequately substantiated" and therefore had the potential to mislead.
The ASA added that BT must not repeat the claims made in the ads unless it holds "documentary evidence to substantiate them" and makes available "sufficient information about their methodology and data for verification".