TalkTalk have responded to the Advertising Standards Authority's (ASA) vow to implement tighter rules around advertising the true cost of broadband deals.
This follows joint research by the ASA and Ofcom that found that current ads for fixed broadband are likely to confuse and mislead customers.
The study found that 81% of viewers were not able to correctly work out the total cost of a broadband contract, while 34% recalled information about the price but only partially or with errors about the broadband service or line rental costs.
Some 22% were unable to work out the total monthly cost after a second viewing, suggesting around 4.3 million UK homes could be in the dark over what they are paying.
Almost two thirds (64%) of those who could not correctly work out the total monthly cost, despite a second viewing, thought the broadband price was the total charge and that line rental costs did not apply.
In addition, 74% said information about the price of introductory deals, discounts, activation, delivery charges and the length of the contract was either fairly or very unclear.
The ASA said the findings showed that the current approach typically taken by advertisers "is likely to mislead consumers and therefore, from May 30, will in all likelihood break the rules".
The ASA will now propose that broadband providers no longer separate out line rental and give greater prominence to contract length, any post-discount pricing and up-front costs.
ASA chief executive Guy Parker said: "It's essential we make sure people aren't misled by pricing claims in broadband ads. That obviously wouldn't be good for them, but nor would it benefit broadband providers, because advertising works better when it's trusted.
A statement released by TalkTalk said: "TalkTalk absolutely supports the ASA's findings and we've already called on Ofcom to bring in all-in pricing.
"It's obvious that a single headline price is much clearer and better for customers, and we're actually already doing it on a pilot project up in York.
"But until the whole market moves to single prices, any company that advertises its products like this will struggle to compete with what look like better deals from other providers. We want Ofcom to be bold and tackle this problem in their strategic review and we would absolutely support them in doing so."