There are so many conflicting figures around, it's hard to tell what's "true" (probably somewhere in the middle).
For example, according to the following links, 55% of the UK population use the internet, and of that, 64.2% are doing so on broadband. That gives a broadband per capita figure of 35.3% which is more than twice the rate stated in the BBC article.
http://www.clickz.com/stats/sectors/...le.php/3588656
http://www.clickz.com/img/Global_Int...mber_2005.html
This survey had broadband per capita penetration in Japan at 36.2% (32.24 million people) as far back as June 2005, even though the OECD study quoted by BBC has it at just 17.5%
http://www.impressholdings.com/relea...20050607_d.pdf
Basically, take EVERY survey with a huge pinch of salt! Nobody seems to know for sure, and every survey seems to have a different methodology.