The BBC has been accused of forcing people to use Microsoft's Windows operating system to access its iPlayer service - which is due to launch later this year.
The Open Source Consortium (OSC), which comprises of organisations, businesses and individual proponents of open-source software, made the charges against the BBC and has threatened to complain to the European Commission (EC).
The group has voiced its concerns to Ofcom, the Department of Trade and Industry and BBC Trust - asking for the BBC to re-examine the effects of the iPlayer being tied to the Windows platform.
In February, when the OSC raised the complaint with Ofcom, OSC chief executive, Iain Roberts, said: "This action from the BBC effectively promotes one operating system vendor at the expense of others. It is very disturbing that the BBC should be using licence payers' money to affect the operating system market in this way. Imagine if the BBC were to launch new digital channels, but only make them available on a certain make of television - there would be uproar."
The iPlayer catch-up service, which uses Microsoft technology, enables viewers to watch shows up to a month after they are first broadcast. Once downloaded from the player, programmes are only viewable within iPlayer or using Windows Media Player 10 or 11.
The BBC has said that it plans to enable those using other operating systems to access content. However the organisation has said that it is not possible to put a timeframe on when the iPlayer will be available for Mac users although it will be monitoring progress on a six monthly basis.
The OSC argued that as the iPlayer will only work on the Microsoft platform at first it will give the Windows developer an unfair advantage. The group has also said it would like to the see the BBC make the iPlayer work on all operating systems rather than forcing users to choose one desktop technology.
Read more in our blog about the BBC iPlayer's favouring for Windows here.