Hmm. While it's nice to push rendering out to clients for saving your server CPU, that can lead to a suboptimal mobile experience, requiring more CPU and battery power on the mobile device to work on the javascript and render the page. There are other factors, for sure, but you want to be keeping client side javascript down to a minimum. Taking a quick spin through yslow in the mobile browser suggests they've got a n…
n.b. plenty of people looking at the BBC site are still being shown the old style.