A watchdog wants UK broadband companies to change the way they advertise internet speeds so as not to mislead customers.
The Advertising Standards Authority (ASA) wants new rules after finding consumers are unlikely to receive the headline claims quoted by providers.
It said most people think they will get a speed at or close to the headline claim "when, for many, that is not likely to be the case".
The regulator said while most consumers understand the higher the number in the ad, the higher the speed of broadband, many are unclear what this means for them.
Current standards say speeds quoted in broadband adverts need to apply to a minimum of just 10% of all customers, providing they include the words "up to".
The Committees of Advertising Practice (CAP), which sets the standards, has announced it is to review its guidance to advertisers and report back in spring next year.
James Blessing, who chairs the ISPA Council representing broadband providers, said: "The internet industry fully supports the ASA's move to bring the guidance on broadband advertising up to date.
"Crucially, the ASA's research has not identified an effective alternative for the current approach to 'up to' speed claims and ISPA, alongside the wider internet industry, looks forward to supporting the ASA in developing a revised and evidence-based guidance on this."
Previous independent testing by consumer groups found up to three quarters of households are paying for advertised broadband speeds they have never received.
An Ofcom spokeswoman said: "Ofcom is concerned about the gap between advertised broadband speeds and what people actually receive.
"We're pleased that the ASA has confirmed it will bring about changes to advertising practices, so that broadband customers can shop with greater confidence."
Last month, new rules came into effect forcing broadband suppliers to make the pricing on their adverts clearer.
Firms can no longer separate the line rental and monthly cost of an internet connection and must give greater prominence to the length of contracts, prices after any initial discount has ended and up-front costs like installation or activation fees.