UEFA have announced a new three-year deal for Champions League rights with Sky and ITV - but England's top clubs face a major drop in their income from the competition if a European ruling goes against them.
The deal for 2012-2015 is understood to be worth £400million, similar to the current agreement.
But William Gaillard, adviser to UEFA president Michel Platini, said a European Court of Justice (ECJ) case could force a major shake-up in the sale of TV rights across the continent.
Gaillard told Press Association Sport: "This may force us to sell the rights on a Europe-wide basis, which would prevent us from identifying individual national TV pools.
"That will be bad news for clubs in big TV markets such as England."
The Premier League also fear the case - their legal battle against Portsmouth pub landlady Karen Murphy who has used a Greek satellite decoder to screen live matches - could affect their TV income.
The European Union's advocate general Juliane Kokott has already advised that the case means that selling TV rights in separate countries within the EU goes against European law.
The case is now being dealt with by the ECJ with a decision expected in the late summer.
At the moment, UEFA splits Champions League payments among the 32 clubs in the group stage, half depending on far they progress and half on the value of their country's TV deals.
The current £400million deal with Sky and ITV for the UK rights is the biggest in Europe and has seen English clubs earn between £20million and £35million annually from the Champions League alone. Beyond 2015, the future is uncertain.
Under the new deal, ITV will have first pick of the match to show live on Tuesday night and highlights, while Sky Sports have the rights to broadcast live all Champions League matches except for the games on ITV. Sky also has the rights for delayed broadcasts and highlights on both nights.
Gaillard fears that those who say the ECJ often do not follow the advocate general's advice may be burying their head in the sand.
He said: "Most of the time the ECJ follow what the advocate general has said, and the rest of the time partially follow that advice."
In Scotland, where television income from the Champions League is around £10million, and other smaller TV markets, the court case could have a positive effect.
If the case goes against the Premier League it could mean the clubs having to have one single TV deal covering the whole of Europe, rather than domestic TV rights and rights for other individual countries being sold separately.
It could also mean that no matches kicking off at 3pm on Saturday could be shown anywhere in Europe. Currently broadcasts of matches at that time are only blocked for British television, which is why some pub landlords used foreign satellite decoders.
The other alternative would be for the Premier League to throw every single match open to live TV coverage across the whole of Europe.
That would lead to opposition from those who want to keep the Saturday 3pm slot as a closed window in order to protect attendances at games.
Sports minister Hugh Robertson said the Government is putting pressure on the European Commission to maintain the current system.
Robertson said: "I have taken the issue up directly with the European Commissioner responsible for this."
The Premier League said in February any change resulting from the case "would damage the interests of broadcasters and viewers of Premier League football across the EU".