Research from the U.K.’s telecommunications regulator, Ofcom, has found that it’s best to take the claims of broadband providers’ speeds with a big grain of salt.

The agency found that the average speed of broadband connections was 6.2 megabits per second, less than half the advertised speed of 13.8 Mbits/sec. Ofcom is submitting its findings to the Committee for Advertising Practice and Broadcast Committee for Advertising Practice. The two organizations represent the advertising industry in the U.K., and function as self-regulatory bodies. Ofcom says the idea is to give people better information to promote speed-based competition.

Ofcom recommends that instead of maximum speeds the advertising should be based on “Typical Speeds Range,” which would give consumers a better idea of what they would get in real world usage. The maximum speeds, Ofcom says, should only be used in advertising if they are actually achievable by a realistic number of users.

One thing that came out of the research was that the providers’ fastest advertised speeds came closest to the actual ‘up to’ speeds. That is, the fiber optic services, such as BT’s Infinity, advertises up to 40 megabits per second download and 2 Mbits/sec upload. Ofcom found the average download speed was 30.5 to 33 Mbits/sec over 24 hours and 27.4 to 30.3 Mbits/sec from 8 p.m. to 10 p.m. on weekdays.

By contrast, the company’s slower services, which have maximum listed speeds of 20 Mbits/sec and 8 Mbits/sec respectively, performed much worse. For the 20 Mbits/sec service, the average actual speed was 6.9 to 8.7 Mbits, and for the 8Mbit service it was 4.1 to 4.8.

Virgin Media fared better in the tests, with its ‘up to’ 10 Mbits/sec service coming in at 9.5 to 9.7 Mbits/sec, and its 20 Mbits/sec service reaching 17.4 to 18.6 Mbits/sec. The fiber service which advertises up to 50 Mbits/sec hit download speeds of 43.9 to 47.2 Mbits/sec.

But even though Virgin Media had better download speeds, Ofcom says the upload speeds are better with BT. Ofcom says its research showed BT averaged 7.8 Mbits/sec while Virgin Media only reached about 2.8 Mbits/sec.

Ofcom notes in its report that as most broadband in the U.K. is delivered via copper wires using ADSL, the speeds will often be below the theoretical maxima. That is because ADSL speeds are constrained by the length of the copper line to the user.

That was one reason Virgin Media performed better – the company has a network that is largely in urban areas and relatively new. And while fiber optic services performed better overall, only a fraction of the population – 22 percent -- has access to them. The rest must make do with copper lines.

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