Three BT broadband adverts have been banned because of misleading claims about its quality compared with Virgin Media and Sky.
The ads, screened in October, claimed BT Infinity had more responsive online gaming and smoother video than Virgin Media and faster download speeds than Sky.
BT said it "noted" the rulings by the Advertising Standards Authority (ASA) but defended the ads, saying the claims were based on independent testing by the broadband availability service SamKnows and additional tests on speeds.
The ASA found the claims had not been adequately substantiated and that the ads were misleading.
It ruled the ads must not appear again in the form complained about.
"We told BT not to repeat the claims in the ads unless they held documentary evidence to substantiate them and made available sufficient information about their methodology and data for verification," the ASA said.
BT said: "BT notes the rulings of the ASA on these ads.
"We believed these claims were fair based on tests carried out by SamKnows and other supporting evidence we offered."