The tests were carried out on a train trip from Cambridge to Bournemouth
Mobile broadband speeds are improving but coverage is getting more patchy, suggests a survey.
Carried out by analysts from comparison site Broadband Genie, the annual test involved using dongles from UK mobile operators during a long train journey.
The top download speed during the trip was three megabits per second (mbps) but the average was just over 1 mbps.
Despite the faster speeds, the tests also revealed that web use failed more often than during 2009.
Dongles from the UK's big five mobile operators as well as Virgin Mobile were put through their paces during a 350-mile train trip from Cambridge to Bournemouth.
The dongles, which help laptops connect to the web, were tested on download and upload speeds as well as how they did with streaming video and music. BBC podcasts, YouTube videos and Spotify music streams were all sampled during the tests.
T-Mobile came out top in the tests because it racked up higher speeds and proved more reliable during the tests.
However, the tests showed wide variation in speeds with some operators only just managing 1mbps while others were regularly twice as fast.
Upload speeds also showed significant variation with the highest speeds of 1.6mbps managed by Virgin Mobile's network but overall averages were regularly under 1mbps.
Streaming of music services and podcasts seemed much improved over 2009's results, found the test, but spotty coverage along train routes meant performance varied significantly.
"Getting mobile broadband to work well on the move presents some real problems for providers, especially in more rural areas," said Chris Marling, editor of Broadband Genie. "But as we work towards establishing a universal minimum standard for UK broadband, these challenges need to be met."