Sky Sports can charge more on BT and Virgin:
http://www.cityam.com/article/sky-sp...-bt-and-virgin
"Virgin Media – which does not make a significant profit on selling Sky Sports – is understood to be likely to pass on the hike, though BT has no plans to do so. If BT chooses to freeze Sky Sports prices on its BT Vision platform, it would cut into its profit per user, signalling its willingness to sacrifice margins in order to sign up customers."
" “BT has no immediate plans to review its prices for Sky Sports 1 and 2,” a spokesperson said. Virgin Media did not comment."