Broadband internet service providers (ISPs) are not legally obliged to provide access to content from website operators that don't pay them.
According to international IT law specialist Pinsent Masons, there is nothing written in consumer laws or telecoms regulation to ensure that broadband suppliers give their customers access to services such as iPlayer or YouTube.
The company's comments came after ISP BT suggested last week that online video content providers such as BBC and Google should pay towards network infrastructure costs because the popularity of their services places a significant strain on bandwidth.
Writing on its website Out-Law.com, Pinsent Masons said that ISPs might consider blocking or slowing access to online video content providers as concern grows over the costs of infrastructure.
"As long as an ISP explains its actions in its fair use policies or statements of terms and conditions it is permitted to block whatever it likes," the law firm explained.
A spokeswoman for regulator Ofcom told the company that its general conditions, which govern the actions of all ISPs, do not stipulate that broadband traffic from different sites must be treated equally.
Earlier this month, BT Retail's Managing Director for Consumer Business, John Petter, hinted at the possibility that the broadband supplier could start charging the likes of BBC and Google, the Financial Times reported.