Mobile broadband provided by O2 loads webpages quicker than any other UK network, research by Ofcom has found.
The regulator carried out 4.2 million speed tests across the country.
It found the average download speed across all networks was 1.5 megabits per second (Mbps), rising to 2.1Mbps in better coverage areas.
The report said speed varied greatly depending on location, and that consumers should check coverage before signing up to tariffs.
Orange fared worst in the research with its average download speeds slower than any other network.
T-Mobile also came out slower than Vodafone, 3 and O2.
O2's chief technology officer Derek McManus said: "Our customers are seeing the benefit from the huge investment we have made in our network. We always aim to deliver the best network experience for our customers and these results are another indicator that we are doing just that."
Everything Everywhere - the name given to the partnership between T-Mobile and Orange - declined to comment on Ofcom's findings.
The report, carried out in conjunction with monitoring specialists Epitiro, ran from September to December last year and dealt with datacards and dongles, but not smartphones.
Ofcom said it hopes to run tests on smartphones soon.
As well as achieving success in the download speed tests, O2 also recorded a lower average latency than 3, Orange and Vodafone.
Latency is calculated by the time it takes for a data packet to travel from a user's PC to a third-party server and back again.
Ofcom chief executive, Ed Richards said: "This research gives consumers a clearer picture of the performance of mobile broadband dongle and datacards as consumers use these services to complement fixed-line services or sometimes as their principal means of accessing online services."
Consumer research showed that 17% of UK homes are now using mobile broadband to access the internet.
Of these, 7% use it as their only means of getting online - a 4% rise since 2009.
The research discovered the average download speed for consumers was 1.5 Mbps, which produced an average load time of 8.5 seconds for a "basic" webpage.
This compared to an average of 6.2 Mbit/s for fixed line broadband, Ofcom found.
However, in areas with good 3G coverage, Ofcom found the average mobile speed rose to 2.1Mbps, dropping to 1.7Mbps at the peak times of between 8-9pm.
On the whole, urban areas performed better than rural areas due to better 3G availability.
The report noted that coverage in cities was highly variable "with no guarantee of good performance" in city centre locations.
Hamish Macleod, chairman of the Mobile Broadband Group, told the BBC that he feels the report paints an unfair picture of mobile broadband by comparing it to fixed rate speeds.
"We recognise this is a useful exercise for Ofcom to do.
"Where I am at issue with Ofcom is the way they have made headline comparisons between fixed broadband and mobile broadband just by using averages.
"It's clear from the research that mobile broadband is a good service, that individual customers can either use it as a complement to fixed broadband or alternatively as a reliable stand alone service."
But not everyone agreed that mobile broadband is a viable alternative to fixed line services.
Charlie Ponsonby, chief executive of comparison service SimplifyDigital said: "The Ofcom report confirms what our customers tell us every day - that mobile broadband is no great substitute for home broadband.
It is on average about three times slower than a standard home broadband connection and often offers very limited data usage, relative to a home broadband connection."
Mobile broadband speeds will remain well below that of fixed broadband speeds until the next generation of mobile coverage - 4G - is rolled out across the UK- a process is expected to begin in 2013.
Everything Everywhere will start the first public trial of 4G in September this year.
Consultation has begun into how the 4G network will be allocated to operators, with an auction due to open early next year.