The British government will block the EU's plan to guarantee net neutrality unless a key part of it is changed, BuzzFeed has learned.

The revelation comes a month after the European Parliament voted through legislation that would introduce net neutrality across the EU.

Net neutrality is the principle that all internet traffic should be treated equally. In practice, this makes it more difficult to censor the internet and stops internet service providers from restricting access to data-heavy services such as NetFlix.

But the government has told BuzzFeed that it will not accept the legislation as it stands because the law would restrict the state's ability to block access to sites.

"We wouldn't support anything that restricted our ability to block illegal material," a government spokesperson said. "We do not support any proposals that mean we cannot enforce our laws, including blocking child abuse images."

The government says it is only concerned by the restrictions on web blocking, but in 2010 Conservative culture minister Ed Vaizey said he supported a two-speed internet to ensure the "smooth running" of networks – effectively ruling out net neutrality.

"We have got to continue to encourage the market to innovate and experiment with different business models and ways of providing consumers with what they want," he said at the time. "This could include the evolution of a two-sided market where consumers and content providers could choose to pay for differing levels of quality of service."