Brits will now have the option of leaving a broadband contract without being penalised if they find within three months of signing up that their actual speed is significantly below the estimate they were given when purchasing the package.
Ofcom has added the clause into its Voluntary Code of Practice on Broadband Speeds, which came into force in December 2008 and has been signed by 95 percent of UK ISPs.
According to the watchdog, ISPs must provide Brits with an estimated range of speeds they can expect on their line. This "durable record" will be used should consumers find the speeds are not provided and want to extract themselves from their contract.
"The ISP must tell the customer their minimum guaranteed access line speed and explain that if the technical fault cannot be fixed, then the customer will have the opportunity to leave their contract immediately and without any penalty provided this is within a three month period of the start of their contract, or longer (if the ISP so chooses)," Ofcom said.
Ofcom also strengthened the code's requirements to offer consumers a more accurate and consistent estimate of the maximum speed likely to be achievable on their line.
The amendments to the Code of Practice won't come into force for 12 months.
"While we support Ofcom's efforts to ensure broadband providers are more open with consumers about what they should expect from their broadband connection, we feel that Ofcom have missed an opportunity to redraft the code itself in a format which consumers could better understand," said Sebastien Lahtinen, co-founder of Thinkbroadband.com
"Instead of providing additional guidance notes which would assist providers in interpreting the code, Ofcom have created an even more complex code, which is less accessible to the average user."
See also: Ofcom to act on broadband speeds