The gap between what broadband firms advertise as download speeds and the rates people actually get is getting wider, a watchdog report has revealed.
This is despite average UK broadband speeds increasing by 27% since April 2009.
Ofcom said ordinary internet surfers are getting no more than half the internet speed for which they signed up to.
The reality is even more stark for the three quarters of the UK's online population which still use DSL broadband, which runs through copper telephone lines rather than through fibre optics. Ofcom found DSL lines managed an average 6.5Mb a second, despite internet firms claiming speeds of "up to" 20-24Mb a second.
The watchdog's response is to revise its voluntary code of practice, of which all the main internet service providers are signatories, in an attempt to ensure fairer and more honest practice. Ofcom has added a provision which allows people to cancel their broadband deal if the broadband speeds are not up to scratch and if the firm does not fix the problem.
Ofcom's Ed Richards said: "Actual speeds are often much lower than many of the advertised speeds which makes it essential that consumers are given information which is as accurate as possible at the point of sale; this is what the new code is designed to deliver."
Firms are now being asked to use the less deceptive "typical speed range" rather than "up to" a certain speed on advertising to more accurately reflect what people will be paying for.