A UK court has ruled that pay TV broadcaster BSkyB must make its Sky Sports 1 and 2 channels available on rival BT's YouView service.
BT has been challenging BSkyB's dominance of sports broadcasting, and last year complained to the regulator, Ofcom, about airing the channels.
Ofcom first said the channels should be available to other pay TV providers four years ago.
The ruling served the interests of consumers and competition, Ofcom said.
The judgement from the Competition Appeal Tribunal (CAT) is an interim ruling. There will be a further ruling in due course when more evidence has been assessed, but it is thought unlikely that Wednesday's decision will be undone.
Ed Richards, Ofcom's chief executive, said in a statement: "After more than four years of litigation and legal challenges, Ofcom's 2010 pay TV decision continues to serve the interests of UK consumers and this ruling is consistent with our original decision."
The majority of BT's one million TV customers are on YouView.
The company said: "BT has always maintained that Ofcom was correct to impose the 'wholesale must offer' (WMO) on Sky and this remedy remains essential to address the significant competition concerns with Sky's supply of its channels. We look forward to being able to offer these channels to our YouView customers very shortly."
However, a Sky spokesman indicated that the company would continue to challenge the ruling. "Today's judgment is a purely interim measure with no impact on the ongoing legal process or the CAT's previous dismissal of Ofcom's core argument in favour of WMO.
"Ofcom itself is reviewing WMO in light of market developments and we continue to believe that this unwarranted obligation should be removed entirely."