In the spring, BT's wholesale division will start offering Content Connect, a new service which enables internet service providers (ISPs) such as Sky and TalkTalk to use BT's network to charge major content operators for high-speed video delivery.
As bandwidth-heavy services such as the Google-owned YouTube and BBC iPlayer place a heavy load on ISP networks, there is a belief in the industry that it is fair to charge them for optimum delivery. Critics, however, have accused BT of breaking the core principle of net neutrality, in which all content delivered over the internet is treated equally.
Jim Killock, executive director of campaigning organisation Open Rights Group, said: "We are talking about ISPs competing with the internet for content delivery. Whether films, music or gaming services, the idea is that ISPs will deliver this stuff better and more reliably than the internet.
"The result could be a fundamental shift away from buying services from the internet to bundled services from ISPs: which would reduce competition and take investment away from internet companies. That would be bad for everyone."
BT today defended Content Connect, arguing that the service will not lead to a two-tier internet. The firm said that it "supports the concept" of net neutrality, but ISPs should have the freedom to charge providers for a "higher quality" of service delivery.
"Contrary to recent reports in the media, BT's Content Connect service will not create a two-tier internet, but will simply offer service providers the option of differentiating their broadband offering through enhanced content delivery," a BT spokeswoman said.
"BT supports the concept of net neutrality but believes that service providers should also be free to strike commercial deals should content owners want a higher quality or assured service delivery."
First unveiled in September, the Content Connect platform - developed in collaboration with Cisco - will enable ISPs to cache content deep within BT's network, meaning it can be delivered much closer to the end user, thus avoiding heavy network congestion.
BT believes that the platform will eventually allow broadcasters to provide video content over the web, including live TV, with an "assured level of service all the way to the viewer, providing uninterrupted access even at peak times".