Broadband is getting faster in the UK but some customers are not reaching the speeds that service providers have advertised, shows a survey.
Broadband speeds are on the rise
The average UK broadband download speed is now 2Mbps, up from 512Kbps three years ago, says thinkbroadband.com.
The figures are based on more than a third of a million speed tests carried out by the website's users.
But many people who have been sold "up to 8Mbps" services are still getting substantially slower connections.
"Compared to a couple of years ago the average has gone up," confirmed Andrew Ferguson, editor of thinkbroadband.com.
"But the survey shows that whilst a number of providers are marketing products as an 'up to 8Mbps' service, it is clear that some of them have a fair proportion of customers still on fixed 512kbps, 1Mbps or 2Mbps services."
For some customers the maximum speed they can attain is tied to the quality of the telephone line and distance from the exchange.
But Mr Ferguson said some broadband providers were keeping people on fixed connections to save costs.
"Because the broadband they are giving people still fits into the description of 'up to 8Mbps' that they are selling people, they think that's fine."
Mr Ferguson said people should be told that the connection they are getting is "rate adaptive".
"People see the 'eight' and that sticks in their heads. Rate adaptive ADSL means it runs as fast as the line can tolerate."
He encouraged people to ask their providers exactly how fast their connection was likely to be before signing new deals.
The fastest connection recorded in the UK was a customer of internet service provider Be at slightly more than 21Mbps.
Mr Ferguson said: "That customer must obviously live very close to the exchange. They are within 100 to 200 metres of the phone exchange."
Be is among a number of firms, including Bulldog and UK Online, who have invested their own money into ADSL2+ technologies, which offer substantial speed improvements.
But these services are often limited to urban areas.
BT Wholesale is currently trialling ADSL2+ technology, which it is expected to roll out to other internet service providers in the next 24 months.
"For those of us who don't live in big cities, that will mean we will get the chance at better speeds," said Mr Ferguson.
While broadband speeds in the UK are set to improve, the country still lags behind Japan and South Korea where speeds of up to 50Mbps are not uncommon.
Mr Ferguson said: "In Japan you will see VDSL services at 50/60Mbps and you think, 'Why can't I have that in Britain?'.
"But in Japan you can roll out whatever you like and you fix problems like interference after. In the UK we like not to have interference."
Faster broadband speeds over telephone lines could potentially lead to interference with radio stations.
The UK regulator wants these problems fixed before the greenlight is given to technologies such as VDSL and VDSL2, which offer tremendous broadband speeds.