TalkTalk has seen an advert for its entry-level SimplyBroadband package banned by the Advertising Standards Authority (ASA).
The regulator upheld a complaint lodged by BT over a press advert, which offered the standalone broadband deal to consumers for "half-price" at £1.75 per month for one year.
The TalkTalk advert stated: "12 MONTHS HALF PRICE Totally Unlimited Broadband...Was £3.50 Package now only £1.75 a month."
BT argued the true price of SimplyBroadband could not be considered £3.50 per month, because the package was so frequently available for less.
The telecoms giant said TalkTalk's £3.50 per month pricing had not been running long enough prior to the introduction of the special "half-price" offer.
The ASA agreed with BT's view that £3.50 per month could not, at the point in time the advert was published, be considered the genuine price of the broadband deal.
Defending its position, TalkTalk provided pricing details for SimplyBroadband over one year prior to the publication of the advert. During this period, the price of the broadband package varied between £1.75 and £3.50 per month.
However, the ASA said that, because pricing within the telecommunications sector "fluctuates regularly", it considered the product’s more recent pricing history was "most directly relevant" to the usual selling price.
"While the package had been priced at £3.50 for 18 days immediately prior to the half-price promotional period, it was priced at £1.75 for approximately the preceding two and a half months," the ASA noted.
"We therefore considered £1.75 was the usual selling price of the product at the time the ad appeared. Because the ad was likely to be understood to mean the usual selling price was £3.50, whereas that was not the case, we concluded that it was misleading."
The ASA banned TalkTalk from repeating the broadband advert in its current form.
It also instructed the service provider to fully substantiate future savings claims in its broadband advertising material.