The average fixed line broadband speed in the UK has increased by 25 percent to 5.2Mbps, says Ofcom.
Speed research by the communication watchdog, which was conducted in conjunction with speed monitoring website SamKnows, revealed that in April 2009 the average download speed was 4.1Mbps.
This was 58 percent of average advertised 'up to' speeds, which was 7.1Mbps. However, the current average speed of 5.2Mbps is just 45 percent of today's average advertised speed with is 'up to' 11.5Mbps.
The watchdog said just under a quarter (24 percent) of Brits have a broadband package that offers a headline or advertised of 'up to 10Mbps' compared to just 8 percent in April last year, showing there is a growing gap between advertised and actual speeds, which Ofcom says is a real concern.
Ofcom's speed tests revealed that on average those on 'up to' 8 to 10Mbps DSL packages were receiving actual speeds of just 3.3Mbps, while those on 'up to' 20 to 24Mbps packages could expect an actual speed of 6.5Mbps.
When it came to cable broadband, the results showed those on 'up to' 10Mbps broadband services were achieving actual speeds of 8.7Mbps and those purchasing packages with headline speeds of 'up to' 20Mbps were receiving actual speeds of 15.7Mbps.
Ofcom also said it found cable service, such as those from Virgin Media, offered average download speeds that were twice as fast as those achieved on DSL services with the same advertised speed.
According to the watchdog, some ISPs have moved away from using 'headline speeds' to advertise their broadband packages, however many continue this practice.
Ofcom says it has been in discussions with the Advertising Standards Authority (ASA), which is currently reviewing the practice, as it believes speeds should only be advertised if some consumers are actually able to achieve them and 'up to' speeds should also include a typical speed range.
"Ofcom's research shows that average speeds have increased which is good news, but there is scope for a further step change in the quality of the UK communications infrastructure," said Ed Richards, chief executive of the watchdog.
"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."
Chris Marling, editor of Broabnd Genie said the average speeds make depressing reading.
"We have been calling for an end to 'up to' speeds for a long time now, as it is clearly a ridiculous concept. An average actual speed of 6.5Mbps on lines supposedly capable of 20Mbps or higher starkly confirms that. It was only a matter of time before the ASA and Ofcom were forced into action" said Marling.
"The UK's broadband suppliers had ample time to come to their senses, but once again waited to be regulated against before acting on their own accord. Only Virgin Media comes out of this round of testing with any credit, although O2 and BE can at least claim to be making the best of our groaning DSL network.
See also: Ofcom to test UK broadband speeds again