The media regulator's latest broadband report claims that customers are benefiting from recent network upgrades by internet service providers (ISPs), such as BT and Virgin Media's fibre broadband.
In May 2012, the average fixed-line residential broadband speed was 9Mbps, which was two-and-a-half times faster than the average speed of 3.6Mpbs recorded in Ofcom's first test in November 2008. It was also up from the average actual speed of 7.6Mbps in November 2011.
Ofcom also found that ISPs are becoming more transparent with their advertising of broadband packages after new rules came into force this year.
The research, using data collected by Ofcom research partner SamKnows, includes for the first time 'superfast' services, such as Virgin Media's 'up to' 60Mbps and BT Infinity's 'up to' 76Mbps services. Ofcom feels that these packages have contributed to an overall increase in average speeds.
Whilst many customers have upgraded to superfast packages, others have benefited from improved speeds as a result of their ISP upgrading its network and boosting rates at little or no additional cost to users.
The proportion of superfast connections (deemed as 'up to' 30Mbps or higher) was 8% in May, compared with 5% in December 2011 and just 2% in May that year.
Average speeds over superfast residential broadband connections are also getting slightly faster, rising from 35.5Mbps in November 2011 to 35.8Mbps in May 2012.
Of the 12 ISP packages studied by Ofcom, Virgin Media's 100Mbps service was rather unsurprisingly found to be the fastest, delivering average actual speeds of 88.3Mbps over a 24-hour period. Virgin has also been upgrading these customers to 'up to' 120Mbps.
The BT Infinity fibre broadband service of 'up to' 76Mbps delivered a 58.5Mbps average actual speed, compared to Virgin Media's 'up to' 60Mbps, which was clocked at an average of 55.9Mbps.
BT's 'up to' 38Mbps package achieved speeds of 32.2Mbps, whilst Virgin Media's 'up to' 30Mbps service had average speeds of 30.1Mbps.
But during busy periods, it was found that a higher proportion of Virgin's cable customers experienced speeds of less than 90% of the average maximum rate compared to BT Infinity fibre customers.
Once again, Ofcom found that cable broadband connections performed better than ADSL broadband, a technology that delivers internet over BT's copper wire telephone network.
Cable broadband generated the greatest increase in average speed in the six months to May 2012, up by 3.6Mbps (26%) to 17.9Mbps.
Over the same period, customers on ADSL services saw their average speeds increase by just 10%, from 5.3Mbps to 5.9Mbps.
However, Ofcom found that average actual speeds recorded for fibre-to-the-street-cabinet (FTTC) connections, such as used for BT Infinity, fell by 12% from 36Mbps to 31.6Mbps over the six-month period.
Elsewhere in the report, Ofcom said that new rules on broadband advertising introduced in April this year are starting to have an impact on how broadband packages are marketed.
The guidance specifically states that packages cannot be advertised as 'up to' a certain rate unless that is achievable by at least 10% of the relevant ISP's customer base.
Many ISPs have now changed the way they advertise broadband services. For example, ADSL2+ - a faster version of copper wire broadband - was previously advertised with its maximum theoretical 'up to' speed of 24Mbps, despite the fact that this was rarely achieved in practice.
"Our research shows that the move to faster broadband services is gathering momentum," said Ofcom chief executive Ed Richards.
"Consumers are benefiting from network upgrades and the launch of new superfast packages, giving them faster speeds and greater choice.
"We are continuing to work with the advertising code-writing bodies and ISPs to ensure that speeds advertised reflect actual speeds experienced, to allow consumers the ability to make informed decisions when shopping around to find the most suitable package."
Consumer group the Communications Consumer Panel welcomed the increase in average UK broadband speeds and greater transparency in broadband advertising.
However, the panel also said that ISPs must ensure they provide customers with clearer information when they buy broadband packages, including that certain factors, such as their distance from the exchange, can severely impact the service they will receive.
"We want to remind ISPs that the Code requires them to give potential new customers information about their likely broadband speeds early in the sales process, before they decide to buy a new service," said panel member Chris Holland.
"Ofcom's recent Voluntary Code of Practice on broadband speeds mystery shopping research found that 7% of consumers would not get a speed estimate via telephone sales - but, even when the consumer was given that information, in just over a third of the cases (34%) it was because the caller had to request it.
"Consumers can only make an informed choice if they can easily compare different packages and providers. We will be watching developments in this area carefully to ensure that consumers are not disadvantaged."